Slang -U-
Uncle Sam
The U.S. government; a patriotic figure who symbolizes the United States.
undie
An abbreviation for underground hip-hop. Originally conceived as a soundalike alternative to "indie," which signifies fey boys with jangly guitars.
Undie is the straight shit, brah. The radio is wack.
upbeat
positive
up (one's) butt
obsessed with another person.
She's totally up his butt.
up the ass
in an excessive amount, usually too much.
I've got e-mail up the ass!
up your sleeve
A hidden advantage; some form of trickery lying in wait.
urp
to vomit. to burp.