noun
(slang, sometimes derogatory) A person who is intellectual but generally introverted.
(informal, sometimes derogatory) One who has an intense, obsessive interest in something.
(informal, sometimes derogatory) A member of a subculture revolving around intellectualism, technology, video games, fantasy and science fiction, comic books and assorted media. [from 1980s]
(informal, sometimes derogatory, dated) One who is stupid and socially inept or unattractive; a social outcast. [from 1970s until early 1990s]