Entry Word: insane

Function: adjective

Meaning: 1 having or showing a very abnormal or sick state of mind <only an insane person would jump off a skyscraper>

Synonyms balmy, bananas, batty, crackbrained, cracked, crazed, crazy, cuckoo, daffy, daft, demented, deranged, loco, loony (also looney), lunatic, mad, maniacal (also maniac), mental, moonstruck, nuts, nutty, screwy, unbalanced, unsound, wacky

Related Words dotty, off; aberrant, delusional, disordered; eccentric, odd, queer, strange; foolish, senseless, witless; irrational, unreasonable; berserk, delirious; depressed; distraught, frantic, frenzied, hysterical

Phrases around the bend, off oneʼs rocker, out of oneʼs head (or mind)

Near Antonyms clear, lucid, rational, reasonable; judicious, sensible, wise; healthy, normal

Antonyms balanced, sane, sound

2 conceived or made without regard for reason or reality <a completely insane plan to fly to the moon on a homemade rocket> — see fantastic 1
3 showing or marked by a lack of good sense or judgment <an insane urge to jump off a cliff> — see foolish 1