Noah Webster's New International Dictionary of the English Language

1. (a.) Exhibiting unsoundness or disorded of mind; not sane; mad; deranged in mind; delirious; distracted. See Insanity.

2. (a.) Used by, or appropriated to, insane persons; as, an insane hospital.

3. (a.) Causing insanity or madness.

4. (a.) Characterized by insanity or the utmost folly; chimerical; unpractical; as, an insane plan, attempt, etc.