Motor Boat Material, Any woman with large breast that you can put your face in between and motor boat
yo, shorty over there got some nice MBM's.

Look at the MBM running this way.
by Tony and Luis July 6, 2011
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mom behind me. Used in AIM to tell the perosn your mom or some one else is behind you and to keep converstion clean.
Bill: Lets smoke that weed on Saturday

Bob: MBM

Bill: wat you doin this weekend?
by Ryan March 11, 2005
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Married Black Male, Married African-American Male. same as mwm but black. usually found in classifieds, etc
MBM looking for a MBW for a discrete hook-up.
by Chanticlear January 7, 2008
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Stands for mom behind me. This is used when you are texting on the phone and u don't want the other person to send inappropriate language to you, the person behind you does not have to be your mom just someone you don't want seeing anything.
Guy: you're so sexy
Girl: hold up! mbm
by allons-ycompanion March 13, 2015
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Message Board Misunderstanding: Used to connote sarcasm on a message board, or to apologize in advance to whomever you might offend...
hey zeke. you're an asshole. <mbm.
by Ms. Topaz September 9, 2005
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