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.

by Hector the molester July 28, 2010

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."

by ActuallyMike December 31, 2015

Underlust

Underlust is Au, of undertale where soul falls into the underground but its not the monster's think. So they send it to W.D Gaster to research about the soul and Gaster finds out that, He can eject the lust in monster's, And then every monster in the underground is filled with lust, Including, Toriel, Sans, Papyrus, Undyne, Alphys, Mettaton/Happstablook and Asgore, And then Asriel is in this world, Toriel and Asgore Where happy about there child and then, Asriel dies and turns in to dust, Toriel and Asgore in Sadness, The ashes of Asriel go on a flower bed and the flowers (Which where roses) made Rose and then Happstablook and Alphys meet up in a Human-Fan-Club and Sence Happstablook likes being on stage Alphys decided to build, Happstablook a Robot body (That was a Sexual related body cause of course not) And Mettaton is on stage and got tons of fans, One night though everything changed, After a show Mettaton was Sexually Assaulted and Beaten by one of his "Fans" Sence Mettaton Was badly beaten Alphys Was trying to repair Mettaton, By doing Minor repairs, and giving him glasses. And is a tad-bit shy now. And a Teen falls into the Underground to soon realize that there is sexual reference's Every where. And that where we are now.
Weapons: Toriel/Old police Batons, Sans/A ripoff of Asriel's Swords, Papyrus/Fists, Undyne/Whip, The rest of these are fists.
I'll leave the rest of the detail's to you.

Guy 1:Man, underlust makes me look like a Virgin.
Guy 2: I like underlust, although it has a sour taste its actually pretty good.

by Etp445 (Unoffical) September 17, 2020

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

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

by desmian March 21, 2022

Underbuck

Setting your price so it's lower than your competitors.

I can barely sell any weed here lately, because John around the corner is out here underbucking everyone selling the same quality stuff, for half of the price!

by ALL BIZ March 17, 2016

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.

by Tinnysman July 11, 2018