fess up
phrasal verb.phrasal verb. to admit that you did something wrong or made a mistake. You use this when you finally tell the truth about something you were hiding.
phrasal verb. to confess or admit to a fault, error, or minor crime; marked informal register, often used in contexts involving social accountability or lighthearted interrogation.
Come on, fess up—who ate the last cookie?
After the manager found the broken window, the new employee decided to fess up and apologize.
Although he initially denied any involvement in the prank, he eventually had to fess up when the security footage was reviewed.
Clipping of confess up.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
often used as an imperative or followed by the preposition 'to' and a noun or gerund.
explain that 'fess' is a clipped form of 'confess'; highlight its informal nature compared to 'admit' or 'confess' to help students with register awareness.
He fessed up his mistake.He fessed up to his mistake.when mentioning the specific mistake, the preposition 'to' is required after the phrase.
Last updated April 24, 2026