lunatic

B2 Topic:People & Society

US /ˈluːnətɪk/ UK /ˈluːnətɪk/ See IPA manual

Meanings

1

noun
a person with severe mental illness

The lunatic was taken away by the authorities.
2

noun
someone who acts wildly or foolishly

He's a lunatic for trying to climb the mountain alone.
3

adj
extremely foolish or irrational

It was a lunatic plan with no chance of success.
4

adj
(archaic) relating to the moon or believed to be affected by its phases

Old beliefs held that lunatic behavior followed the lunar cycle.

Thesaurus

Synonyms

1 noun · a person with severe mental... madman madwoman maniacpsychotic

2 noun · someone who acts wildly or... crank fanatic eccentricoddballweirdo

3 adj · extremely foolish or... crazy ridiculous absurd insane preposterous

4 adj · (archaic) relating to the... lunarmoonstruckselenic

Opposites

sane rational sensible

Simplified etymology

Lunatic entered English in the Middle Ages and comes from Latin luna, meaning “moon.” The word reflects the former belief that the phases of the moon could affect people.

Etymology

From Latin lūna ("moon") + -āticus ("pertaining to"), giving lunaticus ("moonstruck, insane"); via Old French lunatique and Middle English lunatike (14th c.) into Modern English lunatic, reflecting the medieval belief that lunar cycles affected behavior.

Topics

People & Society Register & Style

External links

# lunatic

**Type:** Word
**Level:** B2
**Part of speech:** noun, adj
**IPA (US):** /ˈluːnətɪk/
**IPA (UK):** /ˈluːnətɪk/

## Meanings
1. a person with severe mental illness
2. someone who acts wildly or foolishly
3. extremely foolish or irrational
4. (archaic) relating to the moon or believed to be affected by its phases

## Examples
- The lunatic was taken away by the authorities.
- He's a lunatic for trying to climb the mountain alone.
- It was a lunatic plan with no chance of success.
- Old beliefs held that lunatic behavior followed the lunar cycle.

## Synonyms
- madman
- madwoman
- maniac
- psychotic
- crank
- eccentric
- oddball
- crazy
- ridiculous
- absurd
- insane
- moonstruck

## Antonyms
- sane
- rational
- sensible

## Etymology
From Latin lūna ("moon") + -āticus ("pertaining to"), giving lunaticus ("moonstruck, insane"); via Old French lunatique and Middle English lunatike (14th c.) into Modern English lunatic, reflecting the medieval belief that lunar cycles affected behavior.

## AI Etymology
Lunatic comes from Latin lūna ("moon") + -āticus ("pertaining to"), giving lunaticus ("moonstruck, insane"); via Old French lunatique and Middle English lunatike (14th c.) into Modern English lunatic, reflecting the medieval belief that lunar cycles affected behavior. In current use it is a noun and adjective meaning "a person with severe mental illness". That sense is explained by the older material without requiring a speculative semantic step: the inherited or borrowed base supplies the field of meaning, while the English formation fixes its modern role. The surface form is compositional: its joined elements remain visible in the modern word. The word's history is thus visible in its construction: the components remain interpretable even after the whole expression has settled into a conventional English meaning.

## Topics
- People & Society
- Register & Style

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