LARPer

noun2

1. •
   A person who takes part in LARP (live-action role-play).

   • “Which is why I'm thinking LARPer,” Griffith argued. “Goths interact with non-Goths more in LARPing than anywhere else. And there are non-Goth look people that hang with the Goths.” — 2006
2. •
   (disapproving) Someone who pretends to be part of a movement or group, often for the sake of gaining social status.

   • The extremists were never entirely sure who among them was a true believer, who a mole, and who more a LARPer than otherwise.