fess up
verb
- mode of speaking
Wiktionary
verb
Etymology: Clipping of confess up.
- To confess to something; to admit something.
“"‛Fess up," she persisted. "Have you boys been quarreling again?"”
“And you know, one of the things that I hope is that the American people will find when we make a mistake, we're willing to 'fess up to it and change.”