specifically used as a sly response to people asking questions u don't know the answer to.
idiot #1: hey Joe, what's the state capital of Nebraska?
smarter idiot #2: ehem... ur mom.
An insult
dude - so what did you do last night?
other dude - ur mom.
if somebody said this they talking about ur mom
jake:ur mom is fat
jaquan:"bitch slaps jake to space" dont talk bout my mom
It is a joke about your mom. It is used to insult peeoples moms. YOU MOM
meaning of ur mom= something you can say to anything or anyone. ever.
example= what are you doing? = ur mom
I had veggie soup last night
i had ur mom last night