Definition of "wonk"

Previously, e-reading had been the domain of early adopters and new technology wonks.

2014, Catherine Sheldrick Ross, Pleasures of Reading, The: A Booklover's Alphabet, page 53

This is the sort of standard that the Paul Ryans of the world trumpet to their constituents, to potential campaign contributors and to their peers in Congress. They become “budget wonks” and political superstars, even if their proposals are bound to go nowhere.

2014 March 14, Dean Baker, “Paul Ryan isn't the wonk of Washington – it's time to listen to more good ideas”, in The Guardian‎