lunacy
noun
lu·na·cy ˈlü-nə-sē 
plural lunacies
1
dated
a
: insanity sense 1
b
: intermittent insanity once believed to be related to phases of the moon
2
: wild foolishness : extravagant folly
3
: a foolish act
Synonyms
- absurdity
- asininity
- bêtise
- fatuity
- folly
- foolery
- foppery
- idiocy
- imbecility
- inanity
- insanity
- stupidity
See all Synonyms & Antonyms 
Example Sentences
Quitting her job was lunacy. His idea was considered total lunacy.
Recent Examples on the Web Carrey reminds us why his '60s-film-villain lunacy is the best thing to ever happen to the Dr. Robotnik character. 
Sam Machkovech, Ars Technica, 6 Apr. 2022 But the screwball antics work with credit to Playhouse director David Arisco, who finds the balance between Ludwig’s lunacy and Christie’s suspense. Michelle F. Solomon, Sun Sentinel, 25 May 2022 In this action adventure, the apotheosis of his career thus far, cheerful idiocy occasionally rises to the level of delectable lunacy. Joe Morgenstern, WSJ, 8 Apr. 2022 But Kraje even charms while observing from afar, delighting in the lunacy of others while perched on the crescent moon in the glowing woodland set of scenic designer Anastasia Rurikov Simes. Thomas Floyd, Washington Post, 4 July 2022 Arizona is a reliable punching bag for late-night hosts looking to illustrate the lunacy going on in the country. Bill Goodykoontz, The Arizona Republic, 10 July 2022 From the late 19th and well into the 20th century, a host of conditions, which included lunacy but also feeblemindedness, epilepsy and pauperism, were believed to be caused by an inborn hereditary taint impervious to any and all treatment. Siri Hustvedt, Washington Post, 3 June 2022 In the basement of Baltimore’s Sinai Hospital, Michel Mirowski and Morton Mower began working in the late 1960s on a project that struck some of their colleagues as lunacy. James R. Hagerty, WSJ, 6 May 2022 As the lead thug, Rossi dials up the sadistic lunacy without generating a trace of menace. Rene Rodriguez, Variety, 17 May 2022 See More
Sam Machkovech, Ars Technica, 6 Apr. 2022 But the screwball antics work with credit to Playhouse director David Arisco, who finds the balance between Ludwig’s lunacy and Christie’s suspense. Michelle F. Solomon, Sun Sentinel, 25 May 2022 In this action adventure, the apotheosis of his career thus far, cheerful idiocy occasionally rises to the level of delectable lunacy. Joe Morgenstern, WSJ, 8 Apr. 2022 But Kraje even charms while observing from afar, delighting in the lunacy of others while perched on the crescent moon in the glowing woodland set of scenic designer Anastasia Rurikov Simes. Thomas Floyd, Washington Post, 4 July 2022 Arizona is a reliable punching bag for late-night hosts looking to illustrate the lunacy going on in the country. Bill Goodykoontz, The Arizona Republic, 10 July 2022 From the late 19th and well into the 20th century, a host of conditions, which included lunacy but also feeblemindedness, epilepsy and pauperism, were believed to be caused by an inborn hereditary taint impervious to any and all treatment. Siri Hustvedt, Washington Post, 3 June 2022 In the basement of Baltimore’s Sinai Hospital, Michel Mirowski and Morton Mower began working in the late 1960s on a project that struck some of their colleagues as lunacy. James R. Hagerty, WSJ, 6 May 2022 As the lead thug, Rossi dials up the sadistic lunacy without generating a trace of menace. Rene Rodriguez, Variety, 17 May 2022 See More Word History
Etymology
lunatic
First Known Use
1541, in the meaning defined at sense 1a
Medical Definition
lunacy
noun
lu·na·cy ˈlü-nə-sē
plural lunacies
dated
: mental illness
also : intermittent mental illness once believed to be related to phases of the moon
Legal Definition
lunacy
noun
lu·na·cy ˈlü-nə-sē
: insanity
lunacy
noun
1
as in insanity
a foolish act or idea you want to sneak into the building after the alarm is set—what lunacy! Synonyms & Similar Words
Relevance
- insanity
- idiocy
- absurdity
- madness
- stupidity
- inanity
- imbecility
- craziness
- foppery
- bêtise
- asininity
- folly
- foolery
- fatuity
- buffoonery
- tomfoolery
- absurdness
- nonsense
- witlessness
- foolishness
- blunder
- twaddle
- senselessness
- inaneness
- shenanigan(s)
- drivel
- monkeyshine(s)
- bungle
- howler
- humbug
- flub
- goof
Antonyms & Near Antonyms
- wisdom
- prudence
- sagacity
- discretion
- inspiration
- forethought
- brainstorm
2
as in dementia
a serious mental disorder that prevents one from living a safe and normal life the judge ruled that the lunacy of the accused made him incompetent to stand trial Synonyms & Similar Words
- insanity
- dementia
- hysteria
- madness
- paranoia
- schizophrenia
- instability
- mania
- derangement
- aberration
- rage
- psychosis
- irrationality
- delusion
- neurosis
- frenzy
- delirium
- unreasonableness
- obsession
- abnormality
- phobia
- monomania
- unsoundness
- hallucination
- hypomania
- hallucinosis
- senile dementia
- dementedness
Antonyms & Near Antonyms
- sanity
- rationality
- saneness
- lucidity
- mind
- reasonableness
- normality
- reasonability
- soundness
- rationalness
3
as in madness
lack of good sense or judgment was it desperation or lunacy that caused him to quit his job and move to California without any plan for what to do when he got there? Synonyms & Similar Words
- insanity
- madness
- absurdity
- craziness
- simplicity
- foolishness
- wackiness
- daftness
- zaniness
- inanity
- silliness
- imbecility
- fatuousness
- preposterousness
- nuttiness
- witlessness
- idiocy
- stupidity
- unwisdom
- dottiness
- stupidness
- brainlessness
- asininity
- folly
- fatuity
- senselessness
- nonsensicalness
- irrationality
- balminess
- ridiculousness
- obtuseness
- feeblemindedness
- unreasonableness
- dopiness
- mindlessness
- dullness
- kookiness
- oafishness
- dippiness
- dumbness
- slowness
- simplemindedness
- weirdness
- simpleness
- ludicrousness
- doltishness
- denseness
- fallacy
- vacuity
- dulness
- gormlessness
- dim-wittedness
- laughableness
Antonyms & Near Antonyms
- sanity
- sagacity
- wisdom
- prudence
- rationality
- soundness
- sensibleness
- validity
- reasonableness
- logicality
- sapience
- sagaciousness
- reasonability
- perception
- insight
- sageness
- discernment
- logicalness
- rationalness
- percipience
- superconduction
- superconductions
- superconductive
- superconductivities
- superconductivity
- superconductor
- superconductors
- superconducts
- superconfident
- superconglomerate
- superconglomerates
- superconscious
- superconsciousness
- superconservative
- supercontinent
- supercontinents
- supercontract
- supercontraction
- superconvenient
- supercool
- supercooled
- supercooling
- supercools
- supercop
- supercops