act up

verb

Definition of act upnext
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

Relevance

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

Synonyms & Similar Words

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of act up The black flies are not the only troublesome creature acting up during the unseasonably warm weather. — Clara Harter, Los Angeles Times, 28 Mar. 2026 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 See All Example Sentences for act up
Recent Examples of Synonyms for act up
  1. act out
  2. cut up
  3. misconduct
  4. show off
  5. disobey
  6. horse around
  7. carry on
Verb
  • Traditional Rocky Horror movie showings include a costumed cast acting out the events on screen, with bags of props handed out for audience participation during certain scenes.
    — Anna Ortiz, Chicago Tribune, 28 Aug. 2026
  • Garcia lends the whole song theater-kid interpretation, essentially acting out the lyrics in pantomime, grasping out in front of her, clutching her face.
    — Rebecca Alter, Vulture, 25 Aug. 2026
Definition of act out
Verb
  • What parents can do on hectic mornings Nemours recommends doing as much as possible the night before, from setting out dishes to cutting up fruit.
    — Ashley Lynch, Fort Worth Star-Telegram, 25 Aug. 2026
  • Mix a package of instant potatoes with a half packet of stuffing mix and some cut up salami.
    — Diana Helmuth, Outdoor Life, 20 Aug. 2026
Definition of cut up
Verb
  • In addition, referees were instructed to apply the rules regarding fouls and misconducts more strictly – a move meant to protect players and their inventiveness.
    — Cesar R. Torres, The Conversation, 26 May 2026
Definition of misconduct
Verb
  • The Canadian singer caused a commotion with her ensemble, showing off a head-to-toe Alaïa ensemble from the upcoming Archetypes spring 2027 collection.
    — Karla Rodriguez, Footwear News, 29 Aug. 2026
  • The new couple—who have been linked since they were photographed together at Coachella—dined around the city, showing off their coordinating couple style.
    — Anna Cafolla, Vogue, 29 Aug. 2026
Definition of show off
Verb
  • The violations are disobeying orders and conduct unbecoming an officer.
    — Charlie D'Agata, CBS News, 25 Aug. 2026
  • People don’t do what they’re supposed to, or someone betrays someone else for money or power or spite, or maybe a dragon just disobeys its rider and decides to murder a prince.
    — Brian Grubb, Vulture, 10 Aug. 2026
Definition of disobey
Verb
  • Also, don’t get too out of control horsing around with friends in the water.
    — John Natale, Hartford Courant, 16 Aug. 2026
  • According to McGrady, the only royal who didn’t enjoy the time away in the Highlands was the late Princess Diana, who didn’t fit in with the family’s outdoorsy vibes and didn’t enjoy riding horses around the property due to a fall as a child.
    — Meredith Kile, PEOPLE, 12 Aug. 2026
Definition of horse around
Verb
  • Devers hit a three-run home run in the second inning, Drew Gilbert hit a pair of rally-sparking doubles, and five Giants relievers carried on the momentum that Whisenhunt appeared to be building before his elbow lit up.
    — Andrew Baggarly, New York Times, 25 Aug. 2026
  • What began as a single title has since grown into more than 400 books and counting, with Mike Berenstain now carrying on the family legacy.
    — Madeleine Wright, CBS News, 25 Aug. 2026
Definition of carry on

Browse Nearby Words

actuators
act up
acuity
See all Nearby Words

Cite this Entry

“Act up.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/act%20up. Accessed 1 Sep. 2026.

Copy Citation
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?

Why does English have so many silent letters?

7 Pairs of Commonly Confused Words
See More

Popular in Wordplay

See More

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of

Even More Words That Sound Like Insults But Aren't

Even More Bird Names that Sound Like Insults (and Sometimes Are)

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
skateboard-dog-hat
Wordmaxxing Slang Quiz Give your vocabulary a glow up by getting sendy w...
See All