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Added 10 October 2026

lunatic

/ˈluːnətɪk/ noun

In Latin: lunaticus Wiktionary

noun Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about lunatic at Wordnik → Where our words come from →

An insane person.
A reckless impetuous irresponsible person.

adjective

Insane and believed to be affected by the phases of the moon.

Origin

From Middle English lunatik, from Old French lunatique, from Late Latin lunaticus (“moonstruck”), derived from Latin luna (“moon”), the connection stemming from the belief that changes of the moon caused intermittent insanity.

From Wiktionary, via Kaikki.org (CC BY-SA)

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