undercunnder 

1) To present yourself as something you are not in order to convince someone that you are not a Pig.

I was so stonned I almost didnt see the undercunnder cop comming.

undercunnder by MBC March 31, 2003

Undercunterated 

When you underestimate how much of a cunt someone is

Wow, I undercunterated her!

How did you undercunterate that bitch?!

Undercunterated by Daker June 16, 2015

underbunder 

British slang for Underwear.

Used when you are talking about someone you either don't like or you're best friends with them and you're just messing about.

Example:
"Omg, we can all see his fat underbunder from here, I am uncomfortable."

Example:
"Get your fat underbunder off that chair!"

Example:
"Please take you and your assed underbunder out of here."

underbunder by igorpleaseshutup November 9, 2020