genius
/ˈdʒiːniəs/·지니어스·noun
great natural ability; a very gifted person
LatinCEFR B1
Root
Latin 'genius' (guardian spirit of birth, innate nature)
Latin genius (a guardian spirit attending one's birth) → Middle French genie → English genius
In a word
Ancient Romans called the guardian spirit attending a person's birth their genius. When someone showed brilliance, people said their genius was strong. Eventually the spirit's name passed to the brilliant person themself. "Genius" wasn't originally a kind of person — it was the name of the spirit standing next to one.
Examples
Einstein was a scientific genius.
It takes genius to make hard things look easy.
Her idea was pure genius.
Related
generategenerousgendergenuineingenious