Wonk
Origin
American English student slang 1954; perhaps navy slang before that. Expert sense popularized in the Presidency of Bill Clinton, 1993.
Origin uncertain, possibly from wonky ("shaky, unreliable") or wank, wanker http://www.etymonline.com/index.php?term=wonk, or simply expressive. "WithOut Normal Knowledge" or simply "know" spelt backwards. http://www.worldwidewords.org/qa/qa-pol1.htmhttp://wordsmith.org/words/wonk.html yeah, right...
Full definition of wonk
Noun
wonk
(plural wonks)- (derogatory) An overly studious person, particularly student; a nerd.
- (by extension) A policy wonk or other intellectual expert.