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

With insane gas prices in places like California this year, a Volt, or something like it, appeals to a significant swath of the American green-car-buying public. — Brooke Crothers, Forbes.com, 23 Aug. 2026

If that insane offer doesn’t plug the leak, the fire sale begins. — Dieter Kurtenbach, Mercury News, 19 Aug. 2026

That’s a big memory for me as a kid, so having that happen is insane. — Los Angeles Times, 19 Aug. 2026

These are eight facts about women in medical research that are downright insane, infuriating and, in some cases, just unbelievable. — Emily Cegielski, Flow Space, 19 Aug. 2026