act up

• (UK) enPR: ŭp, IPA^(key): /ækt ˈʌp/, [ækˈtɐʔp]
• (US) enPR: ŭp, IPA^(key): /ækt ˈʌp/, [ækˈtʌp̚]
• (General Australian) IPA^(key): /ækt ˈap/, [ækˈtäp]

  • Audio (General Australian):

    (file)

• Rhymes: -ʌp

act up (third-person singular simple present acts up, present participle acting up, simple past and past participle acted up)

1. (intransitive, idiomatic) To misbehave; to cause trouble.

   Synonyms: carry on, act out, play up

   Coordinate term: kick up

   My allergies act up during hay fever season.

   Children may act up in class in an effort to get attention.

   My car started acting up after I drove through that huge puddle.

2. (intransitive, 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.

   • 2017, Adam Kay, This Is Going to Hurt: Secret Diaries of a Junior Doctor:

     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.

• throw a tantrum

• caput