acted up; acting up; acts up
1
: to act in a way different from that which is normal or expected: such as
a
: to behave in an unruly, recalcitrant, or capricious manner
the children were acting up
b
: show off
c
: to function improperly
this typewriter is acting up again
2
: to become active or acute after being quiescent
her rheumatism started to act up
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Synonyms
Examples of act up in a Sentence
Verb
the two-year-old was acting up in church so much that her dad had to take her outside
you should have seen the boys acting up when they put on their aprons
Recent Examples on the Web
Jenelle Riley, Variety, 20 Dec. 2024
Exactly zero of the acts up for Best Rock Performance, Best Rock Song, or Best Rock Album are first-time nominees.
—Justin Curto, Vulture, 8 Nov. 2024
Service animals, emotional support animals, acting up.
—Armstrong Williams, Baltimore Sun, 20 Mar. 2024
But in 1954, Brando was at the height of his talents, bringing American acting up to and past to the British standard for the first time, with a realism achieved through that delicate balancing of gender qualities that pretty much no one before or after mastered in the same way.
—Allen Farmelo, Robb Report, 23 July 2024
See all Example Sentences for act up 
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Verb
At a group dinner, Benji begins acting up and acting out, eventually storming away — only to be heard playing the piano in the next room, and beautifully.
—Jenelle Riley, Variety, 20 Dec. 2024
Exactly zero of the acts up for Best Rock Performance, Best Rock Song, or Best Rock Album are first-time nominees.
—Justin Curto, Vulture, 8 Nov. 2024
Service animals, emotional support animals, acting up.
—Armstrong Williams, Baltimore Sun, 20 Mar. 2024
But in 1954, Brando was at the height of his talents, bringing American acting up to and past to the British standard for the first time, with a realism achieved through that delicate balancing of gender qualities that pretty much no one before or after mastered in the same way.
—Allen Farmelo, Robb Report, 23 July 2024
See all Example Sentences for act up
Dictionary Entries Near act up
Cite this Entry
“Act up.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/act%20up. Accessed 30 Dec. 2024.
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