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noun

lunacy

LOO-nuh-see

Lunacy (noun) means Madness or insanity, especially of a kind once believed to come and go with the phases of the moon. Example: “His wild rants were dismissed as lunacy by everyone who knew him.”

noun
1
Madness or insanity, especially of a kind once believed to come and go with the phases of the moon.
"His wild rants were dismissed as lunacy by everyone who knew him."
2
Something reckless or deeply misguided, without necessarily involving actual mental illness.
"Driving in that storm would be pure lunacy."
"Spending the whole budget on one advert was lunacy."

How to use lunacy

Learner’s notes

In plain EnglishMadness — either literal insanity or, more commonly today, just a wildly reckless or foolish idea.

Common pairings
sheer lunacy an act of lunacy

Word forms

lunacies plural

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His wild rants were dismissed as _____ by everyone who knew him.

Etymology

From lunatic + the noun-forming suffix -cy; ultimately from Latin luna ("moon"), reflecting the old belief that madness waxed and waned with the moon.

Origin: Latin

Related words

Rhymes for lunacy

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Frequently asked questions

What does “lunacy” mean?

The word “lunacy” means madness or insanity, especially of a kind once believed to come and go with the phases of the moon. In plain terms, madness — either literal insanity or, more commonly today, just a wildly reckless or foolish idea.

How do you pronounce “lunacy”?

“Lunacy” is pronounced LOO-nuh-see (/ˈluː.nə.si/ in IPA).

How do you use “lunacy” in a sentence?

Here is “lunacy” used in a sentence: “His wild rants were dismissed as lunacy by everyone who knew him.”

What is another word for “lunacy”?

Words with a similar meaning to “lunacy” include insanity, madness, craziness and craze.

What part of speech is “lunacy”?

“Lunacy” is a noun.

Where does the word “lunacy” come from?

The word “lunacy” comes from Latin. From lunatic + the noun-forming suffix -cy; ultimately from Latin luna ("moon"), reflecting the old belief that madness waxed and waned with the moon.

How many meanings does “lunacy” have?

“Lunacy” has 2 distinct senses listed in this dictionary. The most common is: madness or insanity, especially of a kind once believed to come and go with the phases of the moon.

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Definitions: FreeDict original editorial