act up
— phrasal verb with act uk/ækt/us/ækt/verb
If a person, especially a child, acts up, they behave badly:
Sophie got bored and started acting up.
If a machine or part of the body acts up, it does not perform as well as it should:
My car always acts up in cold weather.
Her shoulder was acting up (= hurting because of injury).
Thesaurus: synonyms and related words
Bad and wrong behaviour
- act
- act out
- angel
- astray
- at your worst idiom
- be no angel idiom
- cross
- go off the rails idiom
- go round
- impossible
- incorrigible
- indecorous
- rail
- rough
- sink
- sink to such a level/such depths idiom
- step
- step out of line idiom
- step/be out of line idiom
- terrible twins
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You can also find related words, phrases, and synonyms in the topics:
Machines - not functioning
Pain & painful