Sports . a failure to execute a play, stroke, or maneuver properly; an error.

Informal . a mistake.

Informal . to make a mistake.

Theater . to fail to answer one's cue or to answer another's cue.

to give the wrong cue to.

noun

erratum , inaccuracy , incorrectness , lapse , misstep , mistake , slip , slip-up , trip , blooper , err , error , fluff

verb

mistake , slip , slip up , stumble , trip up