What is (someone) playing at?

What is (someone) playing at?

What is someone's agenda or ulterior motive? Why is someone doing this? I can't figure out why Janet is suddenly volunteering for a job she said she would never do. What's she playing at? What are you playing at trying to go on a date with my sister?
See also: play, what
Farlex Dictionary of Idioms.

what’s somebody ˈplaying at?

used to ask in an angry way about what somebody is doing: What do you think you’re playing at?
See also: play, somebody
Farlex Partner Idioms Dictionary
See also:
  • (one's) game
  • a hidden agenda
  • a mystery to (one)
  • be (on) the wrong side of (an age)
  • be on the right/wrong side of 40, 50, etc.
  • balmy
  • a change of heart
  • able to do
  • able to do it
  • appear to