Definition of play at:
(v) :
To do something in a manner that lacks seriousness, commitment, or professionalism.
(v) :
To pretend to be a different person while playing a game.
(v) :
(especially in rhetorical questions) Used to suggest that someone is doing something very wrong, or incorrectly, usually with the possibility of causing damage or harm.
(v) :
Used other than figuratively or idiomatically: see play, at.
(v) :
(archaic) To play (a game).