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to act up

to act up

15 5.9
A body part or health problem that starts to cause pain again after getting better
  • phrasal verb
  • /ækt ʌp/
: resentirse
  • One of my wisdom teeth has been acting up lately, she said.
  • allergies acting up
  • arthritis acting up
  • back acts up

Yeah, I feel like my allergies are going to act up from that.

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Examples

  • My back is acting up again.

  • At first, I thought it was my middle ear acting up.

    Fiction book (2002)
  • Is your back acting up again?

  • Tell him that my back thing is acting up and I have to stay in bed for a few days.

  • I said I was as hard a worker as the next man, except when my back was acting up.

    Fiction book (1991)
  • Your allergies acting up again?

  • My allergies were acting up.

    Fiction book (2002)
  • My back is acting up, so I'm unable to run at the moment without aggravating that.

  • Yeah, that's right; my sinuses are acting up again.

    Fiction book (1993)
  • My back is acting up again, making it hard to sit for long periods.

Synonyms

to flare up
vsto act up
23 4.7

To become suddenly stronger or worse, often for a short time

worsens again after improvement but not necessarily suddenly
to inflame
vsto act up
  • Specialized
13 5.3

To make part of the body red, swollen, and painful

causes pain or problems again without implying inflammation
to seize up
vsto act up
8 6.5

Stop working properly because of damage or lack of oil

becomes painful or troublesome again without necessarily stopping movement
to recrudesce
vsto act up
  • Specialized
9.9

Start again after a quiet time, usually something bad

occurs again after improvement but emphasizes pain or body problems
to enflame
vsto act up
  • Specialized
7.2

To make a part of the body red, swollen, or painful

causes pain or problems again rather than naming inflammation specifically

Antonyms

∞ 1.0

To make something better

481 1.2

To become healthy again after an injury, illness, or emotional pain

How Troublesome

to flare up
23 4.7
to act up
15 5.9
to hurt
∞ 1.0
to trouble
174 1.8
to ache
25 1.0

Surface Forms

act up infinitive
acted up past
acted up past participle
acting up present participle
acts up third person singular

Morphology

act + up

The base verb 'act' (to behave) makes the human-behaviour sense partly derivable, but the particle 'up' does not literally mean 'badly' or 'malfunction' and its contribution is idiomatic and variable. Because the combination suggests abnormal or problematic behaviour/malfunction but requires familiarity with phrasal-verb patterns to predict both human and mechanical senses, the expression is only partially predictable to a B1 learner.

Etymology

Act up gives the picture of a body part that suddenly starts to behave badly: the verb act (behave) together with up (more active) makes you imagine a knee or back becoming painful again. So act up means 'to cause pain' or 'become a problem again'.