Are you out of your mind?

Are you out of your mind?

What you're saying, suggesting, or proposing is outrageous, ridiculous, or crazy! A: "All we need to do is destabilize the global economy, and our company would be poised to assume total market dominance!" B: "You're willing to plunge the world into chaos just to become a bit more profitable? Are you out of your mind?" A: "I want to go sky-diving for my 40th birthday!" B: "Are you out of your mind? There's no way you're getting me to jump out of an airplane, even on your birthday!" A: "I was working 100-hour weeks to get this done on time." B: "Are you out of your mind? You're going to drive yourself to an early grave!"
See also: of, out
Farlex Dictionary of Idioms.
See also:
  • you're out of your mind
  • You're out of your mind!
  • you must be out of your mind
  • you've got to be out of your mind
  • if it ain't broke don't fix it
  • if it ain't broke, don't fix it
  • be (all) of a piece
  • cockamamie
  • cockeyed
  • sublime to the ridiculous