A NPC is a non-player character. In a role playing game a NPC is any character that is not controlled by a player. So don't be a player, be an NPC!! Same as the NPC (line) shirt just with what NPC stands for so the un-cool people do not have to ask you when you are rocking this shirt.
Tags: d-and-d, dungeonsanddragons, dungeon-master, dungeons, pen-and-paper-gaming