geek

1. A carnival performer specializing in bizarre and unappetizing behavior.
2. (colloquial) A person who is intensely interested in a particular field or hobby and often having limited or nonstandard social skills. Often used with an attributive noun.
3. (colloquial) An expert in a technical field, particularly one having to do with computers.
4. (colloquial) The subculture of geeks; an esoteric subject of interest that is marginal to the social mainstream; the philosophy, events, and physical artifacts of geeks; geekness.
5. (colloquial) An unfashionable or socially undesirable person.