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
Brian Lowry, CNN, 2 July 2024
Nobody's that good an actor to keep this act up for 50 years.
—Daniela Avila, Peoplemag, 27 June 2024
The parents of children who act up in the Jersey Shore town of Margate City will be fined this summer for their badly behaved kids.
—Brian Niemietz, New York Daily News, 13 June 2024
In November of last year, the car started acting up — the transmission seemed to have failed after just a few months of ownership.
—Andy Kalmowitz / Jalopnik, Quartz, 11 June 2024
See all Example Sentences for act up 
Verb
Babies remain the last vestige of scoundrels in sequel terms, so naturally the movie introduces a son to Gru (voiced as usual by Steve Carell) and Lucy (Kristen Wiig) who, semi-amusingly, can’t stand his dad, screaming or acting up in some other way every time Gru picks him up.
—Brian Lowry, CNN, 2 July 2024
Nobody's that good an actor to keep this act up for 50 years.
—Daniela Avila, Peoplemag, 27 June 2024
The parents of children who act up in the Jersey Shore town of Margate City will be fined this summer for their badly behaved kids.
—Brian Niemietz, New York Daily News, 13 June 2024
In November of last year, the car started acting up — the transmission seemed to have failed after just a few months of ownership.
—Andy Kalmowitz / Jalopnik, Quartz, 11 June 2024
See all Example Sentences for act up
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'act up.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
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 27 Jul. 2024.
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