When game information outside of what is available in a game is used to give a player an advantage in-game. Most commonly seen and frowned upon in many forms of role playing especially when consent has not been given.
Example a.

A dungeons and dragons adventure team comes across an unknown monster in-game. The metagamer knows this monster through out-of-game information. Using this information, the metagamer's character acts upon the monster's weaknesses and attributes despite the character having never seen the monster before.

Example b.

In an online pan-fandom RPG, Ryoga from Ranma 1/2 meets Ken from Street Fighter for the first time and they have a fight to the death. Ken finds some water in a random nearby bucket and dumps it on Ryoga, then proceeds to pummel the life out of Ryoga who is now transformed into a tiny black pig because of his water curse.

In this case, Ken's role player is metagaming.
by erii! November 20, 2010
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The act of using outside or previously gained knowledge within a gaming universe for personal gain or advantage.
John was accused of metagaming when he immediately moved his player to the most protected area of the map to snipe the enemy team members, since he had played the map before and knew from experience.
by m00k July 12, 2003
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Metagaming is when someone playing a game is using perception involving content not included with the game, and using it to their advantage. It is also commonly used, and perhaps not correctly, for when someone has died in a game, remembers their last location, and uses that information to go back there and kill them vengefully.
Player #1 kills Player #2
Player #2: Fuck you I know where you are now!
Player #1: Don't be a dick, that's metagaming.
by Terrum June 14, 2013
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Predicting an opponent's decision in competitive gaming as a result of analysis of the opponent's past decisions.
There is a special set of moves in chess which allows a player to win in four moves. Competitor A has been watching Competitor B play chess, and the past five games in a row Competitor B has attempted to use this four-move win. When Competitor A sits down to play against Competitor B, Competitor A will be metagaming if he/she plays in a way that will easily thwart the four-move checkmate before Competitor B makes it obvious that this is what he/she is doing.

-from Wikipedia
by Denus December 13, 2006
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The highest level of strategy in many complex games, metagame refers to any aspect of strategy that involves thinking about what your opponent is thinking you are thinking.

Metagame comes into play in any game where no single strategy is dominant and opposing sides are aware of multiple strategies that can succeed dependent upon opponents' actions. In order to perform at the highest level, it then becomes necessary to think about what your opponent thinks you will do (which may depend on what he thinks you think he thinks he will do, etc.) and to make decisions based on clues regarding what level they are thinking on.

This term is most commonly used to refer to poker and other complex card games, but is increasingly being used in relation to video games with complicated player vs player elements and even traditional sports.
Normally I would raise the flop with this hand as a semi-bluff, but I've been so aggressive lately that taking metagame into consideration I think he will go all-in with any pair, so instead I'm going to fold.

This guy thinks that I'm going to zergling rush which means he will waste resources defending early. Instead I am going to focus on resource development for mid game, and metagame will win me this match.
by dub-jay October 25, 2009
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A common term used in Role-Playing game that tells real life details or something that goes beyond the limits or environment set by the game.
Often frowned apon in Role-Playing.
Some Metagaming noob wanted his job as the Mayor back after he stated that he supposedly "lagged out of the server."

That Metagamer was banned from the server for calling the police to report a marijuana plant sticking through a wall outside a player owned apartment.
by Knight Vista December 27, 2010
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Noun; A person playing a ttrpg (tabletop role playing game) who will search the entire universe for every edition (even for other games) for feats and abilities to break the game as much as possible.
1. UGH, Jimmy took Monkey's Grip and Giant's Strength from completely different editions of the game and now he does 20 damage at lvl 1. He is SUCH a metagamer.
by Natural1 May 3, 2018
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