The phrase "to fess up" means to admit or confess something, usually relating to a mistake or wrongdoing. It is an idiomatic expression that comes from the word "confess," which means to acknowledge and accept responsibility for one's actions.
Sentences with «to fess up»
And, since I'm already confessing things I might as well fess up about my addiction to trays. (atthepicketfence.com)
Warring factions of people finally fessing up to the fact that the other side can do something right — that's pretty cool. (automobilemag.com)
Thanks so much Maureen for taking the time to comment, I'm glad I was able to «get you», and thanks for fessing up that I did. (careertrend.net)