admitting something.
Kudos to the teen for fessing up the whole story.
by happymonday October 30, 2013
Come on fess up. I know you aren't really that sick.
by The Return of Light Joker November 14, 2009
"Fess up or we'll all be caught"
by Pete January 20, 2004
To diss; to insult.
Jane (to John): you're dumb stupid.

Joe: ohhhhh, you just got fessed up.
by Yugojokes July 14, 2011
Also used as "fess it up"
1) To give or relinquish.
2) A request for booger.
1.
Person A: I'm goin' to the store - you want something?
Person B: Yeah, get me a dope and a moon pie.
Person A: Fess up some $, biatch!

2.
C'mon baby fess up some of that booger!

3.
Dude, did you get her to fess it up last night?
by [KmA] Jumper May 25, 2005
Talking disrespectful to another individual which can cause confrontation .
by SlangGang101 March 14, 2018