1.
If you play up something, you emphasize it and try to make people believe that it is important.
The media played up the prospects for a settlement...
His Japanese ancestry has been played up by some of his opponents.
≠ play down
PHRASAL VERB : V P n (not pron) , V P n (not pron) , also V n P
2.
If something such as a machine or a part of your body is playing up or is playing you up , it is causing problems because it is not working properly. ( BRIT INFORMAL )
The engine had been playing up...
It was his back playing him up.
PHRASAL VERB : usu cont , no passive , V P , V n P
3.
When children play up , they are naughty and difficult to control. ( BRIT INFORMAL )
Patrick often plays up when he knows I’m in a hurry.
PHRASAL VERB : V P