solitary
/ˈsɒlɪt(ə)ri/·솔리터리·adjective
done or existing alone
LatinCEFR B2
Root
Latin 'solitarius' (alone), from 'solus' (alone)
Latin solus → solitarius → Old French solitaire → English solitary (14th c.)
In a word
Latin solitarius (being alone). Sister adjective to solo from the same root, solus. Within the sol family, solitary marks the state of being — solo (alone in act, in performance), solitary (alone in existence), solitude (aloneness itself), sole (the one and only). A musical 'solo' is momentary; a 'solitary' life is durative — one root split across two time-scales.
Examples
He led a solitary life.
A solitary candle lit the room.
Solitary confinement is severe punishment.
Related
solitudesolitarilysolosoleisolate