Something that can be said as an answer to everything, it can also replace a noun in a sentence. You can also turn around a few words from the last sentence said and add ''ur mom'' somewhere.

Note how when used, it will cause the person you're talking with to automaticaly have sexual thoughts about his mother.
Random: yeah it's a bit tight
You: ur mom is tight

Random: i'm eating buffalo wings, it's dirty as I type but I really like wings
You: ur mom like it dirty

Random: brb bathroom
Random (several minutes later): back, was a bit long, was out of wiping paper lmao
You: me too but ur mom wiped me

by -Tiamat- February 16, 2008
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a lame comeback often used by annoying 6th grade boys
Someone: "Whatcha Doin?"
Someone Else: "UR MOM!"
by peachjellyontoast April 6, 2009
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A maternal insult, also referred to as a "yo mama" joke, is a reference to a person's mother through the use of phrases such as "your mother" or other regional variants, frequently used to insult the target by way of their mother.
cousin sally: u got a big ahh forehead
you: yk who does got a big forehead?
cousin sally: who?
you: ur mom
cousin sally: ~goes thru all 5 stages of grief~

PS: idc if theres more stages of grief.
by no.luv4zoeyy December 2, 2022
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the #1 thing on my to-do list.
Dude1: bro what's on your to-do list today?
Dude2: ur mom is.
by Anabanana_lamagamagoo December 8, 2021
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ur mom is a meme or would be said as "Your mom"
"i fucked ur mom"
by oilvents October 21, 2021
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defenition 1: ur grandmas daughter, ur dads wife, ur aunts sister, ur cousins aunt, ur uncles sister, ur daughters grandma, ur grandpas daughter, ur sisters/brothers dads wife, UR MOM

defenition 2: a comeback that can replace any noun in a sentence
(also can be used with in bed)
1: is that ur mom? (aka any of the above)

2: ur a party pooper
ur moms a party pooper
(add in bed at the bed of any sentence and it makes sense)
ur a party pooper
ur moms a party pooper
..in bed
COMEBACK: really? usually she gets the party started!
by yer-maum April 25, 2003
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used to replace random nouns in sentences to piss people off
dude stop...dude ur mom can stop
thas the definition...ur moms the definition
by ur mom =P July 17, 2003
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