Outdoor pool, pool umbrellas, pool loungers

Reviews of Grand Millennium Hotel Kuala Lumpur

5 out of 5
Grand Millennium Hotel Kuala Lumpur
160 Jalan Bukit Bintang, Kuala Lumpur

Reviews

8.2

Very good

Rating 10 - Excellent. 430 out of 1000 reviews" "
Rating 8 - Good. 342 out of 1000 reviews" "
Rating 6 - Okay. 129 out of 1000 reviews" "
Rating 4 - Poor. 50 out of 1000 reviews" "
Rating 2 - Terrible. 49 out of 1000 reviews" "

8.2/10

Cleanliness

8.2/10

Staff & service

8.2/10

Amenities

7.8/10

Property conditions & facilities

8.0/10

Eco-friendliness

Reviews

10/10 Excellent

Moinuddin

Travelled with partner
Liked: Amenities
Location
Stayed 4 nights in Feb 2024
Response from The Management on 30 Apr 2024
Dear Moinuddin,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Haitham

Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Excellent
Stayed 2 nights in Apr 2024
Response from The Management on 27 Apr 2024
Dear Haitham,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Tay

Liked: Cleanliness, staff & service, property conditions & facilities
Na
Stayed 3 nights in Apr 2024
Response from The Management on 27 Apr 2024
Dear Tay,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Gerardo

Liked: Cleanliness, staff & service, amenities, property conditions & facilities
The hotel is very comfortable.
Stayed 2 nights in Apr 2024
Response from The Management on 27 Apr 2024
Dear Gerardo,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

6/10 Okay

Ahmad

Travelled with family
Liked: Cleanliness, amenities
Good
Stayed 3 nights in Apr 2024
Response from The Management on 27 Apr 2024
Dear Ahmad,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

William

Stayed 4 nights in Apr 2024
Response from The Management on 15 Apr 2024
Dear William,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Cheng Yam

Set up was very nice and very convenient
Stayed 1 night in Apr 2024
Response from The Management on 15 Apr 2024
Dear Cheng Yam,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Lisa Everlene

Travelled with partner
Liked: Cleanliness, staff & service, amenities, property conditions & facilities
The hotel is located in a convenient area for the shops and transportation. It is safe and clean. I would love to go back and would recommend to others.
Stayed 6 nights in Mar 2024
Response from The Management on 31 Mar 2024
Dear Lisa,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Adeline

Travelled with partner
Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Fantastic location in the heart of KL, steps away from great shopping, food and transport.
Stayed 2 nights in Mar 2024
Response from The Management on 24 Mar 2024
Dear Adeline,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Li Ping

Stayed 2 nights in Mar 2024
Response from The Management on 15 Apr 2024
Dear Li Ping,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Poh Cheong

Travelled with family
Liked: Cleanliness, staff & service, amenities
Area is good for a short vacation. Hotel is located strategically in Bukit Bintang
Stayed 2 nights in Mar 2024
Response from The Management on 16 Mar 2024
Dear Poh Cheong,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Rita, Singapore

Travelled with group
Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Love everything about this hotel. Great customer service. Excellent location. Will definitely be back.
Stayed 2 nights in Mar 2024
Response from The Management on 16 Mar 2024
Dear Rita,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Cindy

Business traveller, Travelled with group
Liked: Cleanliness, amenities, property conditions & facilities
Good location
Response from The Management on 12 Mar 2024
Dear Cindy,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The ManagementGrand Millennium Kuala Lumpur

10/10 Excellent

Soot fern

Travelled with family
Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Staffs are helpful and friendly
Stayed 3 nights in Mar 2024
Response from The Management on 12 Mar 2024
Dear Soot fern,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The ManagementGrand Millennium Kuala Lumpur

10/10 Excellent

Nazaruddin

Travelled with partner
Liked: Cleanliness, amenities
Good clean spacious n all the staffs r helpful n friendly overall stay10 of 10 fully satisfied
Stayed 2 nights in Feb 2024
Response from The Management on 12 Mar 2024
Dear Nazaruddin,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The ManagementGrand Millennium Kuala Lumpur

10/10 Excellent

Timothy

Business traveller
Liked: Cleanliness, staff & service, amenities, property conditions & facilities
A very central hotel within KLCC, and all that there is to offer. Breakfast choices were extensive and tasty. The pool provided welcome relief from the heat, and the gym looks quite well set up. I'd be happy to stay again.
Stayed 4 nights in Feb 2024
Response from The Management on 12 Mar 2024
Dear Timothy,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The ManagementGrand Millennium Kuala Lumpur

10/10 Excellent

Juliet Sandra

Travelled with group
Liked: Cleanliness
Superb location. Didn’t like the showers as they were not powerful, very low pressure! The staff were not very responsive, called them to check on safe as it was not working but no one came to check throughout our 4-day stay.
Stayed 3 nights in Jan 2024
Response from The Management on 12 Mar 2024
Dear Juliet Sandra,Thank you for your feedback on Expedia and we are extremely disappointed to read about the challenges you experienced during your stay with us.Please accept our sincerest apologies for the inconveniences that you had to go through and your comments had been shared with the department head concerned for immediate action as well as to ensure such similar incident do not recur. We wish to assure you that it is certainly not reflective of the usual standards of Grand Millennium Kuala Lumpur and we are continuously putting in more effort to train and develop our team to improve the standard of service.We realized that this experience has marred your impression of the hotel but we hope that you would give us an opportunity to make amends and welcome you back in the not too distant future.Best regardsThe ManagementGrand Millennium Kuala Lumpur

8/10 Good

Ruba, GREYSTANES

Liked: Cleanliness, staff & service, property conditions & facilities
very
Stayed 2 nights in Feb 2024
Response from The Management on 26 Feb 2024
Dear Ruba,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Alan

Liked: Cleanliness, staff & service, property conditions & facilities
Stayed 4 nights in Feb 2024
Response from The Management on 26 Feb 2024
Dear Alan,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Hesham

Travelled with partner
Liked: Cleanliness, staff & service
Great location. Rooms starting to age a bit but clean and comfortable stay
Stayed 2 nights in Feb 2024
Response from The Management on 16 Feb 2024
Dear Hesham,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Stavros

Travelled with family
Liked: Cleanliness, staff & service, amenities, property conditions & facilities
The staff was very kind and helpful. Surrounding of numerous shopping centers. The MRT few meters away. Reach breakfast. To much traffic on afternoon until late at night
Stayed 5 nights in Feb 2024
Response from The Management on 13 Feb 2024
Dear Stavros,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Jocelyn

Stayed 3 nights in Jan 2024
Response from The Management on 31 Jan 2024
Dear Jocelyn,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Christian

Liked: Cleanliness, property conditions & facilities, room comfort
Stayed 2 nights in Jan 2024
Response from The Management on 31 Jan 2024
Dear Christian,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Bridget

Travelled with family
Liked: Cleanliness, amenities
The washroom and air conditioning needs better maintenance
Stayed 3 nights in Jan 2024
Response from The Management on 31 Jan 2024
Dear Bridget,Warm greetings from Grand Millennium Kuala Lumpur and thank you for sharing a review on Expedia.We had the opportunity to review your rating of our hotel and we are sorry that we fell short in your expectations. Please know that we truly appreciate your feedback as it helps us to focus on what is important to our guests. We can assure you that every point of your comment have been well-noted and we have addressed these with the team to be used as an opportunity to continue to train and improve our practices as well as procedures. Please accept our sincerest apologies for the inconveniences caused and we look forward to welcoming you back in the not too distant future.Best Regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Derek

Liked: Cleanliness, staff & service
Stayed 1 night in Jan 2024
Response from The Management on 22 Jan 2024
Dear Derek,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Derek

Liked: Cleanliness, staff & service, property conditions & facilities
Stayed 12 nights in Jan 2024
Response from The Management on 22 Jan 2024
Dear Derek,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

thi

Business traveller, Travelled with partner
Liked: Cleanliness, staff & service, amenities, property conditions & facilities
all good
Stayed 4 nights in Jan 2024
Response from The Management on 25 Jan 2024
Dear Thi,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Linda

Stayed 4 nights in Jan 2024
Response from The Management on 17 Jan 2024
Dear Linda,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

4/10 Poor

Raymond

Business traveller
Disliked: Cleanliness, amenities, property conditions & facilities
Lobby looks decent but the interior seems to be breaking and needs major renovation. The room ceiling leaks and looks old. The health club has closed down too. The price for the room is decent, ard $123 sgd per night. Location is good and convenient though.
Stayed 1 night in Jan 2024
Response from The Management on 17 Jan 2024
Dear Raymond,Warm greetings from Grand Millennium Kuala Lumpur and thank you for sharing a review on Expedia.We had the opportunity to review your rating of our hotel and we are sorry that we fell short in your expectations. Please know that we truly appreciate your feedback as it helps us to focus on what is important to our guests. We can assure you that every point of your comment have been well-noted and we have addressed these with the team to be used as an opportunity to continue to train and improve our practices as well as procedures. Please accept our sincerest apologies for the inconveniences caused and we look forward to welcoming you back in the not too distant future.Best Regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Sujith

Travelled with family
Liked: Staff & service, amenities, property conditions & facilities
It was right in the center of all action. Loved it
Stayed 3 nights in Jan 2024
Response from The Management on 17 Jan 2024
Dear Sujith,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Soon Wah, Waitara

Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Location was excellent
Stayed 8 nights in Dec 2023
Response from The Management on 17 Jan 2024
Dear Soon Wah,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Raidha

Business traveller
Liked: Staff & service, room comfort
Good place for smoking
Good and fair
Stayed 2 nights in Dec 2023
Response from The Management on 17 Jan 2024
Dear Raidha,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

soomin

Stayed 4 nights in Jan 2024
Response from The Management on 17 Jan 2024
Dear Soomin,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Takashi

Stayed 3 nights in Jan 2024
Response from The Management on 31 Jan 2024
Dear Takashi,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Md Meraj

Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Stayed 4 nights in Dec 2023
Response from The Management on 28 Dec 2023
Dear Md Meraj, warm greetings from Grand Millennium Kuala Lumpur and thank you for taking the time to share a review of your stay with us. We are pleased to learn of your excellent experience during your recent visit. All of us here look forward to welcome you back for another memorable stay in the heart of Bukit Bintang soon. Best regards, The Management.

10/10 Excellent

Md Meraj

Travelled with family and small children
Liked: Cleanliness, staff & service, property conditions & facilities
Stayed 7 nights in Dec 2023
Response from The Management on 16 Feb 2024
Dear Md Meraj,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Ibrahem

Stayed 11 nights in Dec 2023
Response from The Management on 28 Dec 2023
Dear Ibrahem, warm greetings from Grand Millennium Kuala Lumpur and thank you for taking the time to share a review of your stay with us. We are pleased to learn of your excellent experience during your recent visit. All of us here look forward to welcome you back for another memorable stay in the heart of Bukit Bintang soon. Best regards, The Management.

10/10 Excellent

Majed

Liked: Cleanliness, staff & service, property conditions & facilities
Nice and clean , near everything
Stayed 2 nights in Dec 2023
Response from Yuvasunthary on 28 Dec 2023
Dear Majed, warm greetings from Grand Millennium Kuala Lumpur and thank you for taking the time to share a review of your stay with us. We are pleased to learn of your excellent experience during your recent visit. All of us here look forward to welcome you back for another memorable stay in the heart of Bukit Bintang soon. Best regards, The Management.

10/10 Excellent

Hon

Stayed 7 nights in Dec 2023
Response from The Management on 17 Dec 2023
Dear Hon,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

4/10 Poor

noor mohamed

Stayed 2 nights in Dec 2023
Response from The Management on 17 Dec 2023
Dear Noor,Thank you for your feedback on Hotels.com and we are extremely disappointed to read about the challenges you experienced during your stay with us.Please accept our sincerest apologies for the inconveniences that you had to go through and your comments had been shared with the department head concerned for immediate action as well as to ensure such similar incident do not recur. We wish to assure you that it is certainly not reflective of the usual standards of Grand Millennium Kuala Lumpur and we are continuously putting in more effort to train and develop our team to improve the standard of service.We realized that this experience has marred your impression of the hotel but we hope that you would give us an opportunity to make amends and welcome you back in the not too distant future.Best regardsThe Management Grand Millennium Kuala Lumpur

4/10 Poor

noor mohamed

Stayed 2 nights in Dec 2023

6/10 Okay

ZAINI

Travelled with family
Liked: Cleanliness, property conditions & facilities, room comfort
Very slow during check in. Need improvement
Stayed 2 nights in Dec 2023
Response from The Management on 17 Dec 2023
Dear Zaini,,Warm greetings from Grand Millennium Kuala Lumpur and thank you for sharing a review on Hotels.com.We had the opportunity to review your rating of our hotel and we are sorry that we fell short in your expectations. Please know that we truly appreciate your feedback as it helps us to focus on what is important to our guests. We can assure you that every point of your comment have been well-noted and we have addressed these with the team to be used as an opportunity to continue to train and improve our practices as well as procedures. Please accept our sincerest apologies for the inconveniences caused and we look forward to welcoming you back in the not too distant future.Best Regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Abdalaziz

Stayed 1 night in Dec 2023
Response from The Management on 10 Dec 2023
Dear Abdalaziz,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

DAVID

Liked: Cleanliness, staff & service, property conditions & facilities
Stayed 4 nights in Nov 2023
Response from The Management on 7 Dec 2023
Dear David,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

8/10 Good

Amna

Travelled with family
Liked: Cleanliness, staff & service, property conditions & facilities, room comfort
Stayed 2 nights in Nov 2023
Response from The Management on 7 Dec 2023
Dear Amna,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

yen pheng

Stayed 2 nights in Nov 2023
Response from The Management on 7 Dec 2023
Dear Yen Pheng, Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

2/10 Terrible

Sanghyo

Travelled with family
Disliked: Staff & service, property conditions & facilities, room comfort
Stayed 3 nights in Nov 2023
Response from The Management on 7 Dec 2023
Dear Sanghyo,Thank you for your feedback on Expedia and we are extremely disappointed to read about the challenges you experienced during your stay with us.Please accept our sincerest apologies for the inconveniences that you had to go through and your comments had been shared with the department head concerned for immediate action as well as to ensure such similar incident do not recur. We wish to assure you that it is certainly not reflective of the usual standards of Grand Millennium Kuala Lumpur and we are continuously putting in more effort to train and develop our team to improve the standard of service.We realized that this experience has marred your impression of the hotel but we hope that you would give us an opportunity to make amends and welcome you back in the not too distant future.Best regardsThe Management Grand Millennium Kuala Lumpur

8/10 Good

Vincent

Liked: Cleanliness, staff & service, property conditions & facilities, room comfort
Stayed 2 nights in Nov 2023
Response from The Management on 7 Dec 2023
Dear Vincent,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

Stewart

Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Hi great stay I just felt that the check I was laborious and inefficient not sure about tourist tax and paying that as cash and the security deposit 200 for what I am a regular guest honestly the check in process needs work or u will lose customers / I really like staying here and generally choose it
Stayed 1 night in Nov 2023
Response from The Management on 28 Nov 2023
Dear Stewart,Warm greetings from Grand Millennium Kuala Lumpur and thank you for sharing a review on Expedia.We had the opportunity to review your rating of our hotel and we are sorry that we fell short in your expectations. Please know that we truly appreciate your feedback as it helps us to focus on what is important to our guests. We can assure you that every point of your comment have been well-noted and we have addressed these with the team to be used as an opportunity to continue to train and improve our practices as well as procedures. Please accept our sincerest apologies for the inconveniences caused and we look forward to welcoming you back in the not too distant future.Best Regards,The Management Grand Millennium Kuala Lumpur

10/10 Excellent

H R

Liked: Cleanliness, staff & service, amenities, property conditions & facilities
Fantastic Location and Great Service throughout my stay
Stayed 3 nights in Nov 2023
Response from The Management on 28 Nov 2023
Dear H R,Warm greetings from Grand Millennium Kuala Lumpur and thank you for staying with us.Thank you for your feedback and we look forward to welcoming you in the not too distant future.Best regards,The Management Grand Millennium Kuala Lumpur