Meaning

noun an insignificant student who is ridiculed as being affected or boringly studious

originAmerican English student slang 1954; perhaps navy slang before that. "Expert" sense popularized in the Clinton administration, 1993. Origin uncertain, possibly from wonky (“shaky, unreliable”) or wank, wanker or simply expressive.

Etymology from Wiktionary, CC BY-SA 3.0