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
AIDS Coalition to Unleash Power
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
Sadie Bell, Peoplemag, 6 Apr. 2024
Their computers begin to act up, and each of the two groups get a classified message: Conflict has broken out between the U.S. and Russia, and the I.S.S. has become a frontline for this war.
—Brian Truitt, USA TODAY, 17 Jan. 2024
That shank was a shocker, and perhaps more concerning was Woods saying his back was acting up int the final hour, leading to the shank.
—Doug Ferguson, USA TODAY, 16 Feb. 2024
Hopefully no one’s acting up on the group vacation.
—Steph Koyfman, Condé Nast Traveler, 26 Jan. 2024
The instrument’s dust cover has been acting up since January 6.
—Amanda Kooser, Forbes, 14 Feb. 2024
Soon after her descent, the walls of the cave grow so wet that the Wi-Fi router begins to act up.
—D. T. Max, The New Yorker, 21 Jan. 2024
Latin act up for songwriter of the year at the 2024 awards.
—Thania Garcia, Variety, 19 Dec. 2023
Conexión Divina — Ashlee Valenzuela, Sandra Calixto and Liz Trujillo — are the only música Mexicana act up for best new artist.
—Thania Garcia, Variety, 14 Nov. 2023
Verb
The biggest trophy of the night is for video of the year, which originally saw 16 acts up for the coveted belt buckle.
—Sadie Bell, Peoplemag, 6 Apr. 2024
Their computers begin to act up, and each of the two groups get a classified message: Conflict has broken out between the U.S. and Russia, and the I.S.S. has become a frontline for this war.
—Brian Truitt, USA TODAY, 17 Jan. 2024
That shank was a shocker, and perhaps more concerning was Woods saying his back was acting up int the final hour, leading to the shank.
—Doug Ferguson, USA TODAY, 16 Feb. 2024
Hopefully no one’s acting up on the group vacation.
—Steph Koyfman, Condé Nast Traveler, 26 Jan. 2024
The instrument’s dust cover has been acting up since January 6.
—Amanda Kooser, Forbes, 14 Feb. 2024
Soon after her descent, the walls of the cave grow so wet that the Wi-Fi router begins to act up.
—D. T. Max, The New Yorker, 21 Jan. 2024
Latin act up for songwriter of the year at the 2024 awards.
—Thania Garcia, Variety, 19 Dec. 2023
Conexión Divina — Ashlee Valenzuela, Sandra Calixto and Liz Trujillo — are the only música Mexicana act up for best new artist.
—Thania Garcia, Variety, 14 Nov. 2023
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.
Word History
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 16 Apr. 2024.
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Kids Definition
act up
verb
: to act in an unruly, abnormal, or annoying way
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