Synonyms of act up in English:

act up


See definition of act up

phrase

1‘the pupils are past masters at acting up in class’

SYNONYMS
misbehave, give someone trouble, cause someone trouble, act badly, get up to mischief, get up to no good, be bad, be naughty, forget oneself, misconduct oneself
clown about, clown around, fool about, fool around, act the clown, act the fool, act the goat, act foolishly
informal carry on, mess about, mess around
British informal muck about, muck around, play up

2‘the computers are always acting up’

SYNONYMS
malfunction, crash, develop a fault, go wrong, break down, give out, stall, be defective, be faulty, fail, cease to function, cease to work, stop working
informal conk out, go kaput, go phut, go on the blink, be on the blink
British informal pack up, play up