in ‧ sane /ɪnˈseɪn/ BrE AmE adjective
1 . informal completely stupid or crazy, often in a way that is dangerous:
That’s an insane risk.
The whole idea sounds absolutely insane to me.
Why did you do that? Have you gone insane?
2 . someone who is insane is permanently and seriously mentally ill so that they cannot live in normal society:
The killer was declared criminally insane.
3 . the insane people who are mentally ill:
a hospital for the insane
4 . drive somebody insane informal to make someone feel more and more annoyed or angry, usually over a long period of time SYN drive somebody mad :
My little brother’s been driving me insane all weekend.
—insanely adverb :
insanely jealous
She giggled insanely.