Synonyms of insanity

insanity

noun

in-ˈsa-nə-tē 

1

as in dementia

a serious mental disorder that prevents one from living a safe and normal life

his incurable insanity requires that he spend the rest of his life in a mental hospital

Synonyms & Similar Words

• dementia
• madness
• hysteria
• schizophrenia
• instability
• paranoia
• mania
• lunacy
• rage
• derangement
• aberration
• delusion
• psychosis
• neurosis
• frenzy
• irrationality
• delirium
• unreasonableness
• obsession
• abnormality
• phobia
• hallucination
• hypomania
• unsoundness
• senile dementia
• monomania
• hallucinosis
• dementedness

Antonyms & Near Antonyms

• sanity
• mind
• rationality
• reasonableness
• lucidity
• saneness
• normality
• soundness
• reasonability
• rationalness

2

as in absurdity

a foolish act or idea

everyone laughed at the latest insanity from the town eccentric

Synonyms & Similar Words

• absurdity
• stupidity
• madness
• idiocy
• craziness
• imbecility
• lunacy
• inanity
• absurdness
• blunder
• foppery
• folly
• foolery
• bêtise
• asininity
• fatuity
• foolishness
• nonsense
• buffoonery
• tomfoolery
• witlessness
• senselessness
• inaneness
• twaddle
• shenanigan(s)
• monkeyshine(s)
• drivel
• flub
• bungle
• goof
• howler
• humbug

Antonyms & Near Antonyms

• wisdom
• discretion
• prudence
• sagacity
• inspiration
• forethought
• brainstorm

3

as in madness

lack of good sense or judgment

had the insanity to think that taking over a government building in protest of our foreign policy was a good idea

Synonyms & Similar Words

• madness
• simplicity
• absurdity
• craziness
• foolishness
• wackiness
• lunacy
• zaniness
• unwisdom
• imbecility
• nuttiness
• silliness
• daftness
• inanity
• stupidness
• fatuousness
• preposterousness
• stupidity
• dottiness
• witlessness
• folly
• brainlessness
• senselessness
• nonsensicalness
• asininity
• idiocy
• balminess
• fatuity
• simpleness
• irrationality
• feeblemindedness
• dullness
• dumbness
• dippiness
• slowness
• unreasonableness
• obtuseness
• mindlessness
• ridiculousness
• simplemindedness
• dopiness
• denseness
• oafishness
• doltishness
• weirdness
• kookiness
• fallacy
• ludicrousness
• gormlessness
• vacuity
• dim-wittedness
• laughableness

Antonyms & Near Antonyms

• sanity
• wisdom
• soundness
• prudence
• sagacity
• rationality
• validity
• reasonableness
• sapience
• sensibleness
• reasonability
• logicality
• perception
• insight
• sagaciousness
• sageness
• discernment
• logicalness
• rationalness
• percipience

Example Sentences

Recent Examples of insanity

Allaway, who had a history of mental illness, was found not guilty by reason of insanity and remains secured in a hospital facility. — Mona Darwish, Oc Register, 14 July 2026

McCall tried to create a contrast between the locations, with the Cady clan’s surroundings having an overgrown quality reflecting the uncontrollable insanity at the heart of the family. — Jim Hemphill, IndieWire, 10 July 2026

Iraq, Canada, United Kingdom, Luxembourg, Qatar, Saudi Arabia After accidentally cursing President Saddam Hussein on stage, theater actor Salem convinces a military court of his insanity to escape a death sentence. — Leo Barraclough, Variety, 6 July 2026

San Francisco trailed 6-1 at the time of Webb’s departure, and given Coors Field’s penchant for insanity, a comeback wasn’t out of the question. — Justice Delos Santos, Mercury News, 4 July 2026