Pronunciation: /ˈækt ʌp/
verb to behave or function in a disruptive or unruly manner
A1 My computer always acts up when I try to print something.
A2 The children started to act up when they got bored during the long car ride.
B1 I had to call a technician because my phone was acting up and not connecting to the internet.
B2 The old car started acting up on the highway, so we had to pull over and check the engine.
C1 The actor was known for his professionalism on set and never acted up during filming.
C2 The new software update caused my computer to act up and crash repeatedly, so I had to revert to the previous version.
adverb in a disruptive or unruly manner
A1 The children always act up when they're tired.
A2 My computer tends to act up when I have too many programs open.
B1 The car started acting up on the highway, so we had to pull over.
B2 The new software update caused my phone to act up and freeze constantly.
C1 The old printer has been acting up lately, so I think it's time for a replacement.
C2 The actor's behavior began to act up during the live performance, causing chaos on stage.
formal The machinery started to act up, causing delays in production.
informal My phone always acts up when I'm trying to send a text.
slang I can't believe my car decided to act up on me right before my road trip.
figurative Her emotions began to act up as she thought about the past.
acted up
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more acting up
most acting up
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has acted up
is acting up
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to act up
acting up
acted up