play at

verb

played at; playing at; plays at

1

: to do (something) in a way that is not serious

They were only playing at trying to fix the problem.

2

chiefly British : to play by pretending to be (someone or something)

She liked to play at doctors and nurses as a child.

—often used in the phrase play at being (something)

boys playing at being soldiers

3

British

—used to say in an annoyed way that one does not know the reason for someone's behavior

What is he playing at?