Webster's Revised Unabridged Dictionary · 1913

Insane

Insane , adjective

[Latin insanus. See In- not, and Sane.]

1.
Exhibiting unsoundness or disorder of mind; not sane; mad; deranged in mind; delirious; distracted. See Insanity, 2.
2.
Used by, or appropriated to, insane persons; as, an insane hospital.
3.
Causing insanity or madness. [Rare]
Or have we eaten on the insaneroot That takes the reason prisoner? — Shakespeare
4.
Characterized by insanity or the utmost folly; chimerical; unpractical; as, an insane plan, attempt, etc.
I know not which was the insane measure. — Southey