larp

To larp is to participate in live action role-playing—a game where participants physically act out characters in fictional scenarios rather than describing actions at a table or through a screen.

Players dress in costume, wield prop weapons, and interact in character for hours or days.

Extended to mean pretending or putting on an act: He's just larping as a tough guy.

The noun larp refers to such an event or the activity itself. (Uppercase LARP is the acronym form.)