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

Underbutt 

When girls wear short shorts and you can see the bottom part of their butts.

Damn did you Ashley's shorts? Her underbutt is completely exposed, and it caused me to bust an instant nut.

Underbutt by Tinnysman July 11, 2018

underbutt 

The second butt created below the original butt by tight underpants, where the elastic is doing all the work, under tight pants.

in my jogging tights i have an underbutt and a muffintop and in between is my ba-donka-donk

underbutt by tiffawiffa April 21, 2009

Underbutt

The portion of a persons rear where the butt cheeks meet the legs

She had a great underbutt...

Duncan likes his underbutt to show a little...

"Have you seen my apple tag... ? I was carrying it around in my underbutt but I seem to have misplaced it.

Underbutt by Randostring February 1, 2026

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

Underbite Chia 

Someone who has a major underbite with crooked teeth. And chia pet hair.

Wow! what an underbite chia you are!

Underbite Chia by shrogor cheet January 8, 2020

UnderLust 

An alternate universe of the game UnderTale containing almost everyone as lust filled monsters, and Mettaton EX as a shy talk show host.

UnderLust was created by nsfwshamecave on Tumblr.com

UnderLust by DepressingVoice16 June 28, 2016