☆ any very studious or hardworking person, often, specif., one preoccupied with a particular subject or field
Origin:
back-form. < wonky
See wonk in American Heritage Dictionary 4
noun Slang
A student who studies excessively; a grind.
One who studies an issue or a topic thoroughly or excessively: “leading a talkathon of policy wonks in a methodical effort to build consensus for his programs”(Michael Kranish).