Definition of "idiosyncrasy" in English

noun

1. A behavior or way of thinking that is characteristic of a person.

2. A language or behaviour that is particular to an individual or group.

3. (medicine) A peculiar individual reaction to a generally innocuous substance or factor.

   • See also: risk factor and host factor

4. A peculiarity that serves to distinguish or identify.

   • He mastered the idiosyncrasies of English spelling and speech.