SpeakUp

Meaning trap

act up

not work properly

to stop working correctly or cause problems, especially for machines, devices, or body parts.

phrasal verbB2common

Don't mix these meanings

Same phrase, different job.

not work properly

to stop working correctly or cause problems, especially for machines, devices, or body parts.

act up (misbehave)

Another meaning of 'act up' is 'misbehave'; compare the examples to keep the meanings separate.

View meaning map

Hear it in context

Notice where the phrase sounds natural.

  • My laptop started acting up right before my online meeting.technology
  • Sometimes, my internet connection acts up during important video calls, which can be very frustrating.IELTS speaking

Fix the pattern

Pattern: subject + act up

WrongMy back has been acting out lately.

RightMy back has been acting up lately.

It's 'act UP' (playing up); 'act out' means express feelings through bad behaviour — a different thing.

Patternsubject + act up

Use it right

Choose the version that sounds natural in speech.

Stiff My laptop has been malfunctioning intermittently all week.

Natural My laptop's been acting up all week.

'Act up' is the casual way to say a device or body part is playing up; 'malfunctioning intermittently' is technical.

Build natural chunks

Words that usually travel with it.

  • act up (device/body part)
    my kneethe enginethe wifiagain

Don't confuse it

Don't confuse with 'break down', which usually means something stops working completely.

Try it in Daily Speak →