Nutcase

Part of speech: noun

Pronunciation: /ˈnʌtkeɪs/

Definitions

1. A person who behaves in an eccentric, irrational, or crazy manner
2. A person displaying unusual, irrational, or eccentric conduct that often leads others to question their mental stability
3. An individual who acts in a wildly irrational, strange, or unpredictable way which raises concerns about their mental health

Etymology: "Nutcase" is a compound of "nut" and "case," and the pairing is what makes it telling. "Nut" has long been slang for the head, and "nut" as a term for a crazy person (as in "nutty") is older than this compound. "Case" in the sense of a person who needs treatment or attention comes from the medical and social-work habit of treating an individual as a file or "case," so a "mental case" was someone whose condition was being managed as a case. Nutcase belongs to a family of similar compounds, including "headcase" and "mental case," which all follow the same pattern of pairing a word for the mind or head with "case." Each one labels a person by a single trait of their condition, and the family shows how English often describes eccentricity or madness in a quick, slightly joking shorthand. The word is written as one unbroken word and works as a noun, applied to a person regarded as eccentric or mentally unstable.

Synonyms: crazy person, lunatic, madman, fool, weirdo

Antonyms: sane person, rational person, normal person