fess up
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fess up
slang To tell the truth about something. "Fess" here is a shortening of "confess." Come on, fess up—you took the money that was on the counter, didn't you? Can you believe that guy fessed up to all three robberies?
See also: up
fess up (to something)
to confess to having done something. (Short form of confess.) I tried to get the boy to fess up to doing it, but he wouldn't do it. Come on, fess up.
See also: up
fess up
v. Slang
To admit to something; confess something: The treasurer fessed up when confronted with the evidence of fraud. The gangster fessed up to the crime.
See also: up