Synonyms of insane

insane

adjective

(ˌ)in-ˈsān 

1

as in mad

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.

Synonyms & Similar Words

• mad
• maniacal
• crazy
• mental
• nuts
• crazed
• psycho
• psychotic
• demented
• disturbed
• deranged
• unhinged
• unbalanced
• foolish
• strange
• irrational
• loco
• nutty
• bonkers
• around the bend
• certifiable
• off
• batty
• daft
• eccentric
• depressed
• cracked
• out to lunch
• haywire
• obsessed
• unsound
• non compos mentis
• brainsick
• unreasonable
• queer
• ballistic
• fey
• distracted
• distraught
• frantic
• delusional
• delirious
• bats
• hysterical
• loopy
• crackers
• odd
• off one's rocker
• off one's gourd
• wud
• delusionary
• off one's head
• disordered
• nuclear
• out of one's head
• oddball
• aberrant
• dotty
• berserk
• touched
• witless
• pixilated
• senseless
• frenzied
• monomaniacal
• raving
• potty
• teched
• ape
• monomaniac
• fixated
• amok
• wigged-out
• bananas

Antonyms & Near Antonyms

• sane
• reasonable
• sound
• balanced
• rational
• clear
• normal
• wise
• sensible
• lucid
• uncrazy
• judicious
• compos mentis
• healthy
• well-adjusted
• unneurotic

2

as in absurd

conceived or made without regard for reason or reality

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

Synonyms & Similar Words

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

Antonyms & Near Antonyms

• reasonable
• realistic

3

as in stupid

showing or marked by a lack of good sense or judgment

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

Synonyms & Similar Words

• stupid
• crazy
• absurd
• mad
• silly
• foolish
• idiotic
• irrational
• lunatic
• ridiculous
• unreasonable
• fool
• dumb
• loony
• nonsensical
• wacky
• zany
• simple
• asinine
• nutty
• preposterous
• kooky
• unwise
• wacko
• weak
• unreasoning
• fatuous
• daft
• cuckoo
• senseless
• daffy
• slow
• inept
• batty
• witless
• out to lunch
• gaga
• barmy
• jerky
• crackpot
• weak-minded
• simpleminded
• brainless
• harebrained
• dippy
• screwball
• dotty
• crackbrained
• loony tunes
• sappy
• moronic
• balmy
• cockeyed
• unreasoned
• meshuga
• illogical
• half-baked
• lunkheaded
• tomfool
• imbecile
• bubbleheaded
• ludicrous
• half-witted
• featherheaded
• thoughtless
• dull
• clueless
• feebleminded
• fruity
• dense
• unintelligent
• obtuse
• mindless
• brain-dead
• dopey
• laughable
• invalid
• opaque
• vacuous
• dim
• doltish
• lamebrain
• thickheaded
• fallacious
• farcical
• dorky
• dunderheaded
• pinheaded
• oafish
• unsound
• nonrational
• thick
• empty-headed
• softheaded
• soft
• surd
• gormless
• knuckleheaded
• clownish
• dim-witted
• chuckleheaded
• airheaded
• notional
• ill-advised
• buffoonish
• slow-witted
• boobish
• chowderheaded
• birdbrained
• unconsidered

Antonyms & Near Antonyms

• wise
• sane
• sound
• sensible
• prudent
• reasonable
• judicious
• intelligent
• clever
• smart
• bright
• logical
• valid
• rational
• sagacious
• sage
• sapient
• brainy
• well-advised

4

as in excessive

going beyond a normal or acceptable limit in degree or amount

wanted an insane amount of money to paint our house

Synonyms & Similar Words

• excessive
• extreme
• steep
• extravagant
• endless
• infinite
• lavish
• exorbitant
• over-the-top
• intolerable
• inordinate
• unconscionable
• unbearable
• undue
• fancy
• baroque
• immoderate
• inappropriate
• devilish
• unmerciful
• plethoric
• overdue
• overextravagant
• stiff
• towering
• overweening
• improper
• limitless
• unjustifiable
• boundless
• a bit much
• immeasurable
• overmuch
• unwarranted
• unseemly
• unrestrained
• thick

Antonyms & Near Antonyms

• reasonable
• moderate
• modest
• inadequate
• insufficient
• deficient
• minimum
• minimal
• temperate
• middling

Example Sentences

Recent Examples of insane

However, Storm co-owner Celeste Keaton was fined and suspended for five games after last Tuesday’s contest, when two girls sitting courtside in support of Cunnigham said Keaton cursed at them and called them insane. — Sabreena Merchant, New York Times, 4 Aug. 2026

In an exchange with two teenage fans who supported Cunningham, Seattle Storm co-owner Celeste Keaton cursed at the girls and called them insane. — Anna Lazarus Caplan, PEOPLE, 3 Aug. 2026

But the legal system’s binary standard—sane and guilty, or insane and not—fits imperfectly with human intuitions about culpability in tragedies like the Clancys’. — Eren Orbey, New Yorker, 30 July 2026

Dominguez, who was declared legally insane the day after the verdicts, will be sent to a state mental hospital. — Sharon Bernstein, Sacbee.com, 27 July 2026