geek

From WikiWord, the free dictionary

/ɡiːk/ English

Definitions

A carnival performer specializing in bizarre and unappetizing behavior.“I once saw a geek bite the head off a live chicken.”
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.“I was a complete computer geek in high school, but I get out a lot more now.”
(by extension) An expert in a technical field, particularly one having to do with computers.“Do you need a hardware geek or a software geek?”
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.

To behave geekishly or in a socially awkward manner, especially when under the influence of drugs or other psycho-active substances, and exhibiting such marked characteristics as hyperactivity, repetitiveness, talkativeness, nervousness, irritability, or paranoia.“Hey, check out that guy...he's really geeking out pretty bad.”