NPC (Non Player Character)
Usually used to refer to characters in an MMORPG that are computer controlled

Non-Player Character. In general, any character (human or otherwise) in a role-playing game that is not controlled by someone playing the game.

In a tabletop RPG, the game master or equivalent (the person running the game) will generally act/speak the parts of all NPCs. These NPCs can range anywhere from an innkeeper the players talk to in order to rent a room to the mysterious woman who follows your party along for her own unknown reasons only to backstab you right when you were starting to trust her. It's up to the GM.

In LARP, the people running the game will again play the NPC parts, and may enlist others to be NPCs. In an ongoing game, LARP NPCs tend to be the characters who are either too temporary or too important to be done by a given player.

In single-player video game RPGs, NPCs are anyone who isn't your party. They generally aren't referred to as such in this context because "the guy next to the weapon shop" works just as well. These NPCs have a set dialog, and most will repeat the same thing they say every time you try to talk to them. Several webcomics have poked fun at this.

And in a MMORPG, the NPCs are the characters controlled by the server. They ofte...

Unimportant people in life. Basically, people you never could or would care about. They may occasionally provide useful information, but they tend to repeat it over, and over, and over, until another important event occurs for them to talk about.

National People's Congress - China's non-elected legislature, it's highest lawmaking body.

Fits perfectly with the common definition of NPC as "Non-Player Character" as the lawmakers in the NPC are government (computer?) controlled and not accountable to the Chinese people.

Fictitious persons who feature heavily in the social lives of some people.