An intellectually brilliant person who excells at using his or her mental abilities for negative or harmful ends; especially a criminal mastermind .
The spirit each person is believed to have in attendance, according to certain religious or mythological traditions, which tries to negatively influence him, and is opposed by his good genius; loosely, someone who is a bad influence.
A person who is considered eminent because of their achievements.
A person of learning, especially one who is versed in literature or science.
A person with significant mental disabilities who is very gifted in one area of activity, such as playing the piano or mental arithmetic.