wonk

1. A student who studies excessively; a grind.

2. 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.
  

.... Am-Heritage

1. a person who works too hard and is considered boring

2. a person who takes too much interest in the details of political policy

• the President’s chief economic policy wonk 
• I made my pitch to the middle management wonk, and then – bliss! (출처: The Independent)
• Yours is the wonky software, and you are the wonk. (출처: USENET)

... 다음영어사전(OALD)