idiosyncrasy
UK: ˌɪd.i.əˈsɪŋ.krə.si | US: ˌɪd.i.əˈsɪŋ.krə.si
n. a distinctive or peculiar feature or characteristic of a person or thing
n. (medicine) an unusual physical or mental reaction to a food, drug, or other substance
The word "idiosyncrasy" originates from Greek idiosynkrasia, combining idios (personal/unique) + syn (together) + krasis (mixture). Originally a medical term for an individual’s unique bodily temperament, it evolved to describe peculiar traits or behaviors. The morphemes reflect the idea of a "personal blend" of characteristics.
Her habit of humming while working is just one of her many idiosyncrasies.
The artist’s idiosyncrasy made his style instantly recognizable.
The drug caused an idiosyncrasy in some patients, leading to unexpected side effects.
His idiosyncrasy of collecting vintage spoons fascinated his friends.
Linguistic idiosyncrasies often reveal a speaker’s regional background.