a fitness nerd; a person who loves working out and gets all technical about technique, form, supplements, protein shakes. The best wieghtlifting moves and generally just talks in a language only other fitnerds can understand.
"Man, look at that fitnerd over there, going off about supercompensation and that meathead has no idea what he is saying. He just keeps nodding and flexing."
by SchwObama February 5, 2010