Roleplaying refers to the changing of one's behavior to assume a role, either unconsciously to fill a social role, or consciously to act out an adopted role.
A role-playing game is a game in which the participants assume the roles of fictional characters and collaboratively create stories. Participants determine the actions of their characters based on their characterization, and the actions succeed or fail according to a formal system of rules and guidelines. Within the rules, they may improvise freely; their choices shape the direction and outcome of the games.
A role-playing game (RPG; often roleplaying game) is a game in which the participants assume the roles of fictional characters.
A computer role-playing game (CRPG) is a broad video game genre originally developed for personal computers and other home computers. ... The earliest CRPGs were inspired by early role-playing games, particularly Dungeons & Dragons, and attempted to provide a similar play experience.
Despite a spectrum of features and game styles, there are some elements common to the CRPG genre. Perhaps the most salient is that of the avatar, with its quantized characteristics that typically evolve over the course of the game, and take the place of the gamer's own skill in determining game outcomes. Another common element in CRPGs is a well-developed fictional setting.
Some MMORPGs also may expect players to roleplay their characters – that is, to speak and act in the way their character would act, even if it means shying away from other goals such as wealth or experience. However, as this behavior is far from being the norm, most MMORPG players never actually play the roles of their characters. Still, MMORPGs may offer "RP-only" servers for those who wish to immerse themselves in the game in this way.