# idiosyncrasy

> English word · Noun · IPA /ˌɪdɪəʊˈsɪŋkɹəsi/

## Definitions
1. A behavior or way of thinking that is characteristic of a person or a group.
2. A peculiar individual reaction to a generally innocuous substance or factor; a risk factor.
3. A peculiarity that serves to distinguish or identify.

## Etymology
First attested in 1604, in modern sense since 1665, from Ancient Greek ἰδιοσυγκρασία (idiosunkrasía, “one’s own temperament”), from ἴδιος (ídios, “one’s own”) + σύν (sún, “together”) + κρᾶσις (krâsis, “temperament”). By surface analysis, idio- + syn- + -crasy.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/idiosyncrasy