Insane — Meaning, Definition & Synonyms

Insane (adjective) — Senses, Synonyms & Antonyms

1. unable to think in a clear or sensible way

   "After learning of the robbery, they were insane with anger and foolishly searched the neighborhood looking for their belongings."

   similar: bats, batty, bonkers (informal + sometimes offensive), brainsick, certifiable (dated, informal + disparaging), cracked (informal + disparaging), crackers (informal + disparaging), crazed (sometimes offensive), crazy (usually offensive), daft (chiefly British, informal), demented, deranged (often offensive), haywire, loco (slang), mad, maniacal, mental (sometimes offensive), non compos mentis, nuts (informal + sometimes offensive), nutty (sometimes offensive), psycho (informal + disparaging), psychotic (sometimes offensive), unbalanced, unhinged, unsound, wud (chiefly Scottish), around the bend, off one's gourd, off one's head, off one's rocker, out of one's head, out to lunch (slang)
   related: dotty, fey, loopy, off, potty (chiefly British), teched, touched, aberrant, delirious, delusional, delusionary, disordered, disturbed, eccentric, odd, oddball, pixilated, queer, strange, foolish, senseless, witless, irrational, unreasonable, amok, ape, ballistic, bananas, berserk, nuclear, depressed, distracted, distraught, frantic, frenzied, hysterical, raving, wigged-out, fixated, monomaniac, monomaniacal, obsessed
   opposite: balanced, compos mentis, sane, sound, uncrazy
   near: clear, lucid, rational, reasonable, judicious, sensible, wise, healthy, normal, well-adjusted, unneurotic

2. conceived or made without regard for reason or reality

   "a completely insane plan to build an opera house in the middle of nowhere"

   similar: absurd, bizarre, crazy, fanciful, fantastic, foolish, nonsensical, preposterous, unreal, wild, off the wall (slang)
   related: implausible, inconceivable, incredible, unbelievable, unimaginable, unthinkable, extravagant, grotesque, bizarro, curious, eccentric, far-out, funny, kinky, kooky, odd, outlandish, out-of-the-way, outré, peculiar, quaint, queer, queerish, quirky, screwy, strange, wacky, way-out, weird, farcical, laughable, ludicrous, ridiculous, Alice-in-Wonderland, Kafkaesque, nightmarish, dreamlike, surreal
   opposite: realistic, reasonable

3. showing or marked by a lack of good sense or judgment

   "an insane plan to blow all of their savings on lottery tickets"

   similar: absurd, asinine, balmy, barmy (chiefly British), batty, brainless, bubbleheaded, cockeyed, crackbrained, crackpot, crazy, cuckoo, daffy, daft, dippy, dotty, fatuous, featherheaded, fool, foolish, fruity (slang), gaga, half-baked, half-witted, harebrained, inept, jerky, kooky, loony, loony tunes, lunatic (informal), lunkheaded, mad, meshuga, nonsensical, nutty, preposterous, sappy, screwball, senseless, silly, simpleminded, stupid, tomfool, unwise, wacko, wacky, weak-minded, witless, zany, out to lunch
   related: airheaded, birdbrained, boobish, brain-dead, chowderheaded, chuckleheaded, clueless, dense, dim, dim-witted, doltish, dopey, dorky (slang), dull, dumb, dunderheaded, empty-headed, feebleminded, gormless (chiefly British), idiotic, imbecile, knuckleheaded, lamebrain, mindless, moronic, oafish, obtuse, opaque, pinheaded, simple, slow, slow-witted, soft, softheaded, thoughtless, thick, thickheaded, unintelligent, vacuous, fallacious, illogical, invalid, irrational, nonrational, surd, unreasonable, unreasoning, unsound, weak, farcical, laughable, ludicrous, ridiculous, notional, buffoonish, clownish, ill-advised, unconsidered, unreasoned
   opposite: judicious, prudent, sagacious, sage, sane, sapient, sensible, sound, wise
   near: brainy, bright, clever, intelligent, smart, logical, rational, reasonable, valid, well-advised

4. going beyond a normal or acceptable limit in degree or amount

   "wanted an insane amount of money to paint our house"

   similar: baroque, devilish, excessive, exorbitant, extravagant, extreme, fancy, immoderate, inordinate, intolerable, lavish, over-the-top, overdue, overextravagant, overmuch, overweening, plethoric, steep, stiff, towering, unconscionable, undue, unmerciful, a bit much
   related: boundless, endless, immeasurable, infinite, limitless, unbearable, unjustifiable, unwarranted, improper, inappropriate, thick, unseemly, unrestrained
   opposite: middling, moderate, modest, reasonable, temperate
   near: deficient, inadequate, insufficient, minimal, minimum