UnderBum 

1. When a female wears really short shorts and reveals the underside of her ass to passers by.

2. God's gift to ass men.

3. Also known as ass cleavage.

Adam: holy shit that chicks ass is hanging out! I think my dick just moved.

Craig: That my friend is some grade A UnderBum.

UnderBum by Hector the molester July 28, 2010

Underbum 

When a female has a second bum

almost like a double chin

"does my underbum look big in this?"

"does this skirt emphasize my underbum?

"underbum is way rank"

Underbum by Chickenpastababy October 13, 2011

underbugger 

A person or annoyance that gets under ones skin and bugs them.

That squeaky door is a real underbugger. I think that new girl is an underbugger, she wont shut up.

underbugger by Christopher Evans August 2, 2008

Underbus

Verb used to describe the act of "throwing someone under the bus" or otherwise admitting someone's wrongdoing for them.

My sister was in trouble with my mom, so she underbussed me for something I did last week, and got herself off the hook.
An underbusser is a grown tattletale.

Underbus by misshappenstanc October 9, 2017

underbun

(Noun) - When a woman's buttocks pleasantly peaks out from the bottom of her respective garments.

"Dude, that mini-skirt on Tami is giving me a great shot of her underbun."

underbun by ActuallyMike December 31, 2015

underbutt 

The distinct area off the bottom that is at the lower part of the gluteus maximus. Usually the underbutt is highly regarded in terms of attractiveness. Often the underbutt is discovered at the beach when womens bikinis do not cover the whole area of the bottom.

Amy has an excellent underbutt

underbutt by bicbiq December 28, 2008

underbuttoned 

when a man leaves too many buttons undone so chest hair is sticking out

alberto: what do you think, am i under buttoned?
rosita: you could make a wig with all the chest hair i can see - when not wearing a tie, two buttons or more is underbuttoned

underbuttoned by desmian March 21, 2022