A person who is intellectual but generally introverted.
A member of a subculture revolving around intellectualism, video games, fantasy and science fiction, comic books and assorted media.
One who has an intense, obsessive interest in something.
A small or puny person; one regarded as insignificant, contemptible.
A fool, a twit.
A person who can be bullied playfully, or easily teased. Sometimes used as a pet-name (often for a younger sibling).