Insane
Part of speech: adjective
Definition: Exhibiting unsoundness or disorder of mind; not sane; mad; deranged in mind; delirious; distracted. Used by, or appropriated to, insane persons; as, an insane hospital. Causing insanity or madness. Characterized by insanity or the utmost folly; chimerical; unpractical; as, an insane plan, attempt, etc.
Example sentence: Insanity - a perfectly rational adjustment to an insane world.
Harebrained
Part of speech: adjective
Definition: absurd, foolish or stupidfrivolous and silly; featherbrained or scatterbrained