Stands for Underage Boobies. While it can be used to describe the breasts of an under-18 year old girl, it is usually used to describe a hot under-18 year old girl that usually provokes a look-but-don't-touch reaction. Alternately it can describe a number of teenage girls when used in a blanket description such as "many UB".

A man with long hair, he contains a laser which he uses to save people from destruction. He also travels through time in a little green box.

Ulan Bator, the capitol of Mongolia. You're supposedly a 'way cool' traveller if you call Ulan Bator 'UB'.

Ultimate Bonding Experience

(with friends you haven't seen for a long time. it usually lasts for one whole day or a weekend getaway.)

the art of signing on to a parental chat board originally aimed at upscale urban mommies and engaging in chat arguments with middle american trailer trash over spanking children and Hezzbollah.

pronouniation: you - bee - ing

UN-BOYFRIEND. Pronounced EWE-BEE. For a commitment-phobic woman, a UB is a man she is dating but she does not want anyone calling him her "boyfriend." She is often dating (and enjoying) several UBs at once. Of the ilk of friends with benefits or fuck buddies.

Unwanted Boner Synonym.
When men get boners when not wanted, or doing a bad time.