act up

1 to behave badly the two-year-old was acting up in church so much that her dad had to take her outside Synonyms act out, misbehave, carry onRelated Words misconduct; disobey, rebel; clown (around), cut up, fool around, horse around, kid (around); show off; roughhouseNear Antonyms obey; acquit, act, bear, comport, conduct, demean, deport, quit; comply, conform; check, collect, compose, constrain, contain, control, curb, handle, inhibit, move, quiet, repress, restrain

2 to engage in attention-getting playful or boisterous behavior you should have seen the boys acting up when they put on their aprons Synonyms cut up, clown (around), fool around, horse around, hotdog, monkey (around), showboat, show off, skylarkRelated Words carry on, misbehave; roughhouse; caper, cavort, disport, frisk, frolic, gambol, lark, rollick, romp; carouse, maffick, revel, roar, wassail