A term used often in place of a lengthy insult regarding someones intelligence, commonly this term is used when the party it is directed at is believed to only have the ability to comprehend two words at one time.
Jimmy says "I went out back yesterday and stole my dogs fun stick"
Bob retorts "Jimbo... You dumb."
A term usually used when someone says something they think is funny but it is actually fucking gay. Best used during the akward silence after the fuck face is done speaking.
"That picture is really cool."
"Thats what she said!"
....................... "YOU DUMB!"
A reference to make toward ignorant and stupid people. Typically used by girl to explain a guy or boyfriend. Can also be used to describe a friend who is a girl when that dont want to except that the guy they are talking to is a Douche.
Boy- I really like you and want to make this work, even though the situation is difficult.
Girl- Awh, but your leaving are you sure?
Boy- Yes im completely sure.
*next day on facebook*
Boy- I dont really like being in a relationship while all of this is going on...blah blah blah
Girl- You just said you wanted to make it work, You Dumb.