id-ee-oh-sin-KRAT-ik
Definition
(adjective) Relating to a distinctive habit, mannerism, or characteristic peculiar to an individual.
Example
Her idiosyncratic habit of color-coding every notebook she owned was odd to others but essential to her.
Word Origin
Idiosyncratic traces back to the Greek idiosynkrasia, a combination of idios (“one’s own”), syn (“together”), and krasis (“mixture” or “temperament”). The word was originally used in medicine to describe a patient’s unique physical constitution or reaction to substances — a blend of qualities belonging only to that individual.
Fun Fact
Idiosyncrasies are the fingerprints of personality — and they’ve long fascinated psychologists and writers alike. Novelists in particular rely on idiosyncratic details to bring characters to life: think of Sherlock Holmes’s obsessive violin-playing at odd hours, or Adrian Monk’s compulsive straightening of picture frames. Research in behavioral psychology suggests that our quirks often form in childhood and become so automatic we’re completely unaware of them — which is why the people around us usually notice our idiosyncrasies long before we do.
