To diss; to insult.
Jane (to John): you're dumb stupid.

Joe: ohhhhh, you just got fessed up.
by Yugojokes July 14, 2011
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
admitting something.
Kudos to the teen for fessing up the whole story.
by happymonday October 30, 2013
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