1.
If you ~ 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 ~, 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