NPC

There are two definitions for this word (both relatively the same). First there’s npc’s in video games, those are “non-player characters” or N.P.Cs. The second definition is a person with such little originality and brain power that they are the most bland human on the planet, sorta like how most Doja Cat fans always say “Does she forget she’s famous???” Or how all Andrew Tate fan says “Common Tate w.”

A play on video games "non-player character" mixed with a play on The Simulation Hypothesis.

An NPC is seemingly a human that is unable to think objectively.

We exist in a simulated reality and some humans take on the role of NPCs, spouting "opinions" they are programmed to spout and repeating in a cult-like manner.

Short for non-player character. These characters are coded to give pre-determined answers and dialogue. These can be found in single player games.

non playable character

usually used to describe someone oblivious that hasn’t “spawned into the world” and acts like they have no thoughts

A play on the term "non--player character" from various forms of interactive gaming (particularly RPGs).

Someone using no critical thought or reasoning skills.
Simply regurgitating a set of arguments and non-sequiturs bequeathed to them by someone else.
Also, once you get it being passed along through multiple generations of NPCs, you get the "Chinese Whispers" effect as well. Drastically ratcheting up the level of crazy.

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 often have some kind of distinguishing feature, such as listing their trade in their status window or their name being displayed in a different color of text. As with single-player RPGs, these NPCs will tend to have set patterns of behavior and often must be interacted with to achieve some objective or another.