1
as in to act out
to behave badly
the two-year-old was acting up in church so much that her dad had to take her outside
Synonyms & Similar Words
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Antonyms & Near Antonyms
2
as in to cut up
to engage in attention-getting playful or boisterous behavior
you should have seen the boys acting up when they put on their aprons
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Example Sentences
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Recent Examples of act up
Bruce, as the stunt shark built to menace them is nicknamed, is acting up and delaying the acting itself.
—
Christopher Smith,
Oc Register,
10 Mar. 2026
Meanwhile, the guests, who have literally just arrived five minutes ago, are already acting up.
—
Rafaela Bassili,
Vulture,
10 Mar. 2026
Excess dust may also cause your allergies to act up.
—
Madeline Buiano,
Martha Stewart,
22 Feb. 2026
Koutouvides transitioned to life after football, found success in real estate development throughout Connecticut, but the pain of losing the Super Bowl twinges and acts up like an old joint injury.
—
Dom Amore,
Hartford Courant,
8 Feb. 2026
See All Example Sentences for act up
Christopher Smith,
Oc Register,
10 Mar. 2026
Meanwhile, the guests, who have literally just arrived five minutes ago, are already acting up.
—
Rafaela Bassili,
Vulture,
10 Mar. 2026
Excess dust may also cause your allergies to act up.
—
Madeline Buiano,
Martha Stewart,
22 Feb. 2026
Koutouvides transitioned to life after football, found success in real estate development throughout Connecticut, but the pain of losing the Super Bowl twinges and acts up like an old joint injury.
—
Dom Amore,
Hartford Courant,
8 Feb. 2026
See All Example Sentences for act up
Recent Examples of Synonyms for act up
Verb
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Lawmakers must resist the temptation to act out of fear to block the growth of AI and its still largely unknown benefits.
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But, again, is acting out of expediency and the desire to streamline a conclusive end the same as delivering a final season representing the best of The Bear?
Verb
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Everything is cut up and put together through chance operations into what Cage called a Musicircus.
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During the matchup, Jeter dove into the stands in the top of the 12th inning to catch a foul ball, emerging from the crowd cut up and bruised.
Verb
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In addition, referees were instructed to apply the rules regarding fouls and misconducts more strictly – a move meant to protect players and their inventiveness.
Verb
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On Monday, OpenAI will host its first-ever Cannes Lions event a few blocks away from the Palais where the awards are given, along the boulevard where the major tech players and ad holding companies have traditionally set up shop to show off to clients.
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The actress showed off micro bangs and a chin-grazing chop for her role as a manager.
Verb
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Santana-Mateo was booked on charges of breach of peace, engaging police in a pursuit, disobeying the direction of officer, reckless driving, failure to obey a stop sign, failure to drive right, failure to obey a traffic control signal and driving the wrong way on a one way.
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In 2024, the agency claimed that X security staff sometimes had to pointedly disobey Musk in order to remain in compliance.
Verb
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Ortiz navigated past 17 other horses around the final turn and made a hard charge down the stretch.
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Ortiz navigated past 17 other horses around the final turn and made a hard charge down the stretch.
Verb
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Do not use to cover a ceiling Do not carry the flag flat — and things should not be carried on it.
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Five of those have powered each variant of Russia’s R-7 rocket family since the 1950s, a legacy now carried on by the Soyuz launch vehicle.
Cite this Entry
“Act up.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/act%20up. Accessed 5 Jul. 2026.
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