Untruth 

Something that cannot be defined as true, yet is not necessarily false; often has a sense of truthiness to it when used in the context of a paradox.

Person 1: The first person to talk to you today is a liar.
Person 2: That would be you...
Person 1: Exactly.
Person 1: So is that true or false?
Person 2: That's an untruth, because you're projecting properties that can't exist; it's neither true nor false and you're an idiot.
Person 1: Untruth isn't a word.
Person 2: Spellcheck disagrees.

Untruth by Zaneshift July 15, 2010

untruthful flexible container of feces 

A polite way of saying the phrase, "lying sack of shit"; it can be used in typed text or spoken.

You claim that Linda stuffs Scottowels down the can?!?
Why Josh, you untruthful flexible container of feces!!!

untruthful flexible container of feces by Telephony May 4, 2013

teller of untruths, your trousers have combusted 

Is a phrase that has become popular after somebody posted on MLIA (mylifeisaverage.com) about translating the phrase "Liar, Liar, Pants on Fire!" to French and back again, and coming up with "Teller of untruths, your trousers have combusted"

Billy: Today I rode a Unicorn
Some Other Guy: Teller of untruths, your trousers have combusted

teller of untruths, your trousers have combusted by Somebody_Else October 26, 2009

untruthatude 

A lie. To speak falsley.
(see also Falcity)

Uh uh, ya honor, that's an untruthatude. I was nowhere in the area when that lady got mugged.

untruthatude by Greg February 10, 2004

UnTruthitude 

the act of being false/fake
a falsity

Liars tell the best untruthitudes

UnTruthitude by B. November 15, 2003

untruthiness 

The opposite of being truthful.

"We are tired of this administrations of untruthiness!"

untruthiness by GoEvilGo April 5, 2007

Untruthitude 

A lie.

Michelle: I'm the sexiest person in the world.
Dan: Untruthitude. That would be me.

Untruthitude by Katiee Drew November 22, 2009