act up

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act up

/ækt ˈʌp/ UK
[ækˈtɐʔp] UK
/ækt ˈʌp/ US
[ækˈtʌp̚] US
/ækt ˈap/ Australia
[ækˈtäp] Australia

Rhymes with -ʌp

verb acts up · acting up · acted up

idiomatic, intransitive To misbehave; to cause trouble. My allergies act up during hay fever season.
Similar: carry on, act out, play up
idiomatic, intransitive 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.

Translations

Every language

verb to misbehave, to cause trouble

Español	alterarse, dar guerra, ponerse en un/ese plan
Français	enquiquiner, énerver, courir sur le haricot, importuner, péter les pruneaux, faire n'importe quoi

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MLA

"act up." Wiktionary, via Micwyn, micwyn.com/word/act%20up. Accessed 6 Nov. 2026.

APA

act up. (n.d.). In Wiktionary, via Micwyn. Retrieved November 6, 2026, from https://micwyn.com/word/act%20up

Chicago

"act up." Wiktionary, via Micwyn. Accessed November 6, 2026. https://micwyn.com/word/act%20up.

BibTeX

@misc{act_up_2026,
  title = {act up},
  howpublished = {Wiktionary, via Micwyn},
  year = {2026},
  url = {https://micwyn.com/word/act%20up},
  urldate = {2026-11-06}
}