exceptional intellectual or creative power or other natural ability

she was a teacher of genius

that woman has a genius for organization

an exceptionally intelligent person or one with exceptional skill in a particular area of activity

a mathematical genius

a person regarded as exerting a powerful influence over another for good or evil

he sees Adams as the man's evil genius

this young man is my good genius, my guardian angel

the prevailing character or spirit of something

Boucher's paintings did not suit the austere genius of neoclassicism