Underoos 

A nickname or name for undergarments that are tight, similar to that of spandex. Also used as a nickname from Tony Stark to Peter Parker in Captain America Civil War.

Tony Stark: "Alright, I've run out of patience, UNDEROOS!" Peter Parker (Spider-Man) flips in.

Underoos by Peterparkerfanfic October 1, 2017

Underwear Streaks 

When you shit yourself, or fart loudly enough that a bit of shit sprays out and stains your underwear with brown streaks.

Dude I just loud farted and it left me with underwear streaks. I may just throw them away at this point.

Underwear Streaks by Soapey August 3, 2019

sans undertale 

a super smash bros ultimate dlc character.

im totally maining sans undertale tbh

sans undertale by Bidoof Is A Pokemon November 3, 2018

Underwater Ceramic Technician 

A fancy name for someone who washes dishes. (Dish pig)

What do you do for work? I'm a doctor"......"Ummm...".....*embarassed* ... "I'm an Underwater Ceramic Technician"...."Wow that sounds impressive!"...."yes..yes it is.

Underwater Ceramic Technician by A Dish Monkey October 16, 2010

Underpants journalist 

A journalist who writes about and/or dressed in their underpants. Often referring to bloggers or freelancers who work from home/their parents' basement.

"TMZ may have broken the 'Michael Jackson is dead' story, but they're still a bunch of underpants journalists."

Underpants journalist by Stable of Crayons July 21, 2009

underverse 

An amazing animated series by Jael Peñaloza. It has finished 1 season with six episodes and has an opening done for the second. It includes Undertale, Underfell, Underswap, Outertale, Fresh, Ink, Error, Dream, Nightmare, Core!Frisk, Cross, Cross Chara, Killer, and partly, XTale.

Person 1: Hey dude you know what Underverse is?
Person 2: No, what is-
Person 1: OH MY GOD IT HAS AAAAAAAAAA

underverse by HelloPersonThatIsReadingThis November 5, 2019

Undercrown 

The shot in porn where all you see is the dude's asshole and balls slapping against whoever they are fucking.

How am I supposed to watch porn when all I see is Undercrown?

Undercrown by thatguy1645 November 26, 2013