A female, not necessarily lesbian, who dresses in athletic attire, i.e. basketball shorts, and has her hair in a ponytail. Has an aggressive demeanor and often presents herself with a masculine/competitive persona.
Mary-Joe makes everything a competition, what an athleta-dyke.
Jill: "You're going to wear that to the mall?"
Monica: "What? These new Jordans go so well with my Nike shorts."
Jill: "Monica, you're such an athleta-dyke."