genius (a person who has great mental ability): He is a genius at mathematics.
prodigy (a child or young person having extraordinary talent or ability): She was an infant prodigy, composing music at the age of five.
brain (a highly intelligent person): He is one of the best brains in this country.
mastermind (someone who plans and organizes a difficult or complicated operation): He was the mastermind behind the bank robbery.
Brainiac American English informal (a very intelligent and brilliant person): She is Brainiac at knowing what will sell.
