expression, i-adjective
not in one's right mind; insane
Used to express that someone's actions, words, or state of mind seem irrational or crazy. Often carries a strong emotional tone of disbelief or shock.
彼がそんなことを言うなんて、正気とは思えない。
I can't believe he would say something like that; he must be out of his mind.
こんな計画を実
Carrying out a plan like this is insane.