Idiosyncrasia

Part of speech: noun

Definitions

1. A distinctive or peculiar characteristic, habit, or mannerism specific to an individual or group; an unusual or unexpected reaction to a drug or substance; a personal quirk that sets someone apart from others
2. An individual's unique behavioral trait or habitual way of acting; a specific atypical response of the body to certain medications; a characteristic idiosyncrasy reflecting personal individuality
3. A personalized and distinctive mode of behavior or thought unique to a person; a specific sensitivity or unusual reaction to a drug or chemical; an eccentric or quirky attribute defining individuality

Etymology: Idiosyncrasy comes from Greek "idiosynkrasia," built from "idios," meaning "own" or "private," "syn," meaning "together" or "with," and "krasis," meaning "mixing" or "blending," which is the same root as "temperament" in the sense of a mixture of bodily humors. Its original sense was medical: an individual's peculiar physical constitution, the way a particular body reacted to food, medicine or climate in ways others did not. Ancient and early modern physicians used the idea to explain why one patient could take a remedy that poisoned another. English borrowed the word in the 17th century, and its sense gradually moved from the body to the mind. A person's temperament and quirks came to be seen as a kind of personal mixture, so by the 1700s it could describe any peculiarity of character. The shift from physical reaction to habit or eccentricity happened gradually rather than at a single point.

Synonyms: idiosyncrasy, peculiarity, quirk, eccentricity, individuality

Antonyms: normalcy, conformity