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.

abnormal absurd apish asinine at fever pitch batty bedlamite befooled beguiled bereft of reason besotted bonkers brainless brainsick buffoonish buggy bughouse bugs certifiable cockeyed crackbrained cracked crackers cranky crazed crazy credulous cuckoo daffy daft dazed delirious deluded demented deprived of reason deranged disordered disoriented distraught dizzy doting dotty dull dumb eccentric fanatical fatuitous fatuous febrile feverish flaky flighty fond fool foolheaded foolish frantic frenetic frenzied fruity fuddled furious futile gaga goofy gulled hallucinated hectic hysteric idiotic imbecile imbecilic inane inept infatuated irrational irresponsible kinky kooky loco loony loopy ludicrous lunatic mad maddened maniac maniacal manic maudlin mazed mental mentally deficient meshuggah mindless moon-struck moronic neurotic non compos non compos mentis nonsensical not all there not right nuts nutty odd of unsound mind off out of it overanxious overdesirous overeager overenthusiastic overzealous perfervid potty psycho psychoneurotic psychotic queer quirky reasonless reckless ridiculous round the bend sappy scatterbrained schizo schizoid schizophrenic screwy senseless sentimental sick silly spaced out spacy stark-mad stark-staring mad strange stupid tetched thoughtless touched ultrazealous unbalanced unhinged unrealistic unsane unsettled unsound wacky wandering wet wild witless