act up definition, meaning - what is act up in the British English Dictionary & Thesaurus - Cambridge Dictionaries Online

Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “act up”

See all translations

act up

phrasal verb with act uk   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).
(Definition of act up from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of act up?
Add Cambridge dictionaries to your browser to your website

Definitions of “act up” in other dictionaries

Word of the Day

decider

a final game or competition that allows one person or team to win, or the winning point scored

Word of the Day

What’s All The Commotion About? (Words to describe sounds)

by Kate Woodford,
May 20, 2015
​​​ In this post we look at a range of words and phrases that we use to describe noise and the absence of noise. Starting with complete quiet, we sometimes use the noun hush to describe silence: A hush fell over the room as the bride walked in./There was a deathly hush (=complete

Read More 

ancestral health noun

May 25, 2015
diet based on the presumed diet of our Palaeolithic ancestors ‘Ancestral health,’ to use a term popular among Paleo followers, has gone mass.

Read More