lunacy

C2+ Topic:Describing People

US /ˈlunəsi/ UK /ˈluːnəsi/ See IPA manual

noun

Meanings

1

noun
foolish or reckless behavior; insanity

Crossing the river in that storm would be sheer lunacy.

Thesaurus

Synonyms

1 noun · foolish or reckless... madness insanity folly foolishness craziness derangement absurdity

Opposites

sanity reason prudence sense

Word family

Related forms lunatic lunarlune

Etymology

From lunatic + -cy, ultimately from Latin luna ('moon'), reflecting the old belief that madness was caused by the changing phases of the moon.

luna Latin *lewk- Proto-Indo-European

View etymology graph ->

Topics

Describing People Word Formation & Derivatives

# lunacy

**Type:** Word
**Level:** C2+
**Part of speech:** noun
**IPA (US):** ˈlunəsi
**IPA (UK):** ˈluːnəsi

## Meanings
1. foolish or reckless behavior; insanity

## Examples
- Crossing the river in that storm would be sheer lunacy.

## Synonyms
- madness
- insanity
- folly
- foolishness
- craziness
- derangement
- absurdity

## Antonyms
- sanity
- reason
- prudence
- sense

## Related Forms
- lunatic
- lunar
- lune

## Roots and Affixes
- Root: luna
- Root: *lewk-

## Etymology
From lunatic + -cy, ultimately from Latin luna ('moon'), reflecting the old belief that madness was caused by the changing phases of the moon.

## AI Etymology
Lunacy comes from lunatic + -cy, ultimately from Latin luna ('moon'), reflecting the old belief that madness was caused by the changing phases of the moon. The etymological trail includes Latin luna and Proto-Indo-European *lewk-. As a noun, lunacy means foolish or reckless behavior; insanity. The same family is visible in related forms such as lunatic, lunar, and lune. Morphologically, the word is built from the elements named in its history, so the modern form preserves a visible compound, prefix, or suffix structure.

## Topics
- Describing People
- Word Formation & Derivatives

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lunacy

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