uncaring 

a trait or quality of not giving a fuck; see chris whitney

The uncaring bastard never gave a damn.

uncaring by trippin October 9, 2004

unleashing the Cheeks 

An unspeakable act of raw power and primative force, in which, an individual plows the nearest warm wet hole with reckless abandon and no regard for the safety of his partner. Punishable by death in most eastern block countries.

Cheekzilla gave his lady brain damage from unleashing the cheeks on her and knocking her head against the head board ALL NIGHT LONG.

unleashing the Cheeks by Siebinator March 23, 2004

uncaringness potential 

the total potential for apathy a person may have

I don't care about my uncaringness potential

uncaringness potential by whathappener September 16, 2009

unbearingly 

Unbearingly is sometimes labelled simply as being an incorrect word, and that the correct word for it is "unbearably." However, in slang, these two words mean different things. Unbearingly means to not be able to stand something to the extent that it is "breaking your back," or troubling you severely, and so you want it to go away (or desire to get away from it).

Here is an example of the difference between "unbearably" (which is a real word) and unbearingly (which is slang and not accepted in formal writing):
"That person was unbearingly nice" means that they were so nice it was unpleasant, perhaps annoying, or in some fashion distasteful. You didn't like it and were happy to get away from them. However, "That person was unbearably nice" means the opposite: the person was so nice, you could not resist them; you couldn't resist falling for their charms, essentially, and will likely look forward to seeing them again.
Of course, slang and "incorrect" terms differ by region, and in some places these two might mean the same thing, but where I live they do not.

unbearingly by StarryMountain April 12, 2012

unnasing 

An aboriginal word, generally used as slang by Australians as a joke. It means "aboriginal vagina".

You have a smelly unnasing don't ya susie

unnasing by Jeremy Loveland January 13, 2015

UnleashingTheBlackMamba 

when your sitting on the shitter and you suddenely shoot out a large log that loops down the toilet and splashes your ass with water

guy 1:hey i was over at the store saw campbell his pants were all wet
guy 2:he must have been UnleashingTheBlackMamba

UnleashingTheBlackMamba by DAblackMAMBA February 27, 2014

unhealing slash 

a vagina

Jenn is so hot, I want to stick it in her unhealing slash

unhealing slash by sean November 19, 2003