play up
US /pleɪ ˈʌp/
UK /pleɪ ˈʌp/
1.
If a machine or part of your body plays up, it does not work correctly.
:
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My car's been playing up all week.
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My knee always plays up in cold weather.
2.
If a child plays up, they behave badly.
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The children started playing up as soon as their parents left.
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He's been playing up all day, I don't know what's wrong with him.