act up — misbehave
phrasal verbB1IELTS 5+informalcommon
to behave badly or not follow the rules, especially for children or pets.
Say it like a native
Textbook The children behaved badly and disobeyed all evening.
Native The kids were acting up all evening.
'Act up' is the natural casual verb for kids misbehaving; the formal paraphrase sounds like a report.
Pattern: subject + act up
In use
- The kids started to act up as soon as the teacher left the room.family
- When my little brother acts up in public, my parents usually try to calm him down quickly.IELTS speaking
Common mistake
✗ The kids are acting up me.
✓ The kids are acting up. / The kids are playing up.
'Act up' is intransitive — no object. (BrE often says 'play up'.)
Common collocations
act up (misbehave)— the kids, started, again, be
Don't confuse it
Don't confuse with 'act out', which means to express feelings through actions.
Related
- act up (not work properly) — Another meaning of 'act up' is 'not work properly'; compare the examples to keep the meanings separate.