lunacy
Americannoun
plural
lunacies-
insanity; mental disorder.
- Synonyms:
- aberration, mania, madness, craziness, dementia, derangement
- Antonyms:
- sanity, rationality
-
intermittent insanity, formerly believed to be related to phases of the moon.
- Antonyms:
- sanity, rationality
-
extreme foolishness or an instance of it.
Her decision to resign was sheer lunacy.
-
unsoundness of mind sufficient to incapacitate one for civil transactions: a former legal term.
noun
-
(formerly) any severe mental illness
-
foolishness or a foolish act
Etymology
Origin of lunacy
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
In the case of “Nirvanna the Band,” I assume the answer to the second question at some point becomes “no,” but it’s all done with a very persuasive mix of vérité style and can-do lunacy.
From The Wall Street Journal • Feb. 12, 2026
It requires little effort to arrange the group’s most unhinged statements into a cornucopia of lunacy, surpassed in recent memory only by the tinfoil conspiracism of QAnon.
From Salon • Jan. 20, 2026
By the third song, Sit Down, Stand Up, they're flexing their musical muscles, with an extended outro of percussive lunacy, aided by US session musician Chris Vatalaro.
From BBC • Nov. 21, 2025
Beware the three Ls: leverage, liquidity and lunacy.
From MarketWatch • Nov. 7, 2025
“Sal, do you detect any signs of lunacy? There doesn’t ap-pear to be any place he could be hiding a gun. His jeans are really tight. Maybe he has a knife tucked into his socks.”
From "Walk Two Moons" by Sharon Creech
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
