See also: foul-up
- (intransitive, slang, idiomatic) To make a mistake, to go wrong.
- You really fouled up this time.
- (transitive) To botch; to make a mess of.
- I fouled up question 3 of the exam.
- (make a mistake): mess up, fuck up (vulgar); see also Thesaurus:make a mistake
- (botch): mess up, fuck up (vulgar)