act up
verbUK /ækt ˈʌp/ · US /ækt ˈʌp/
1
Idiomatic To misbehave; to cause trouble.
- My allergies act up during hay fever season.
- Children may act up in class in an effort to get attention.
1 more example
- My car started acting up after I drove through that huge puddle.
2
Idiomatic To perform the duties of an appointment senior to that actually held; to deputise for a superior.
- Acting up is always recommended when you find yourself under a new boss.
- A few months through my contract, my clinical supervisor said that a registrar was leaving the post early for a research job, and asked if I’d be interested in acting up on the rota.2017, Adam Kay, This Is Going to Hurt: Secret Diaries of a Junior Doctor:
- Related terms
- throw a tantrum