maven

noun1

1. •
   (US) An expert in a given field; also, a person who is interested in and knowledgeable about a particular activity or thing; an aficionado.

   • Connectors know people—lots of people. Mavens know about things. They know, or find out first, what is going on. Connectors, says [Malcolm] Gladwell, need mavens to tell them what to buzz about. — 2003