30.AFK - Away from keyboard, Meaning they aren't playing (eg they've gone for dinner).
29.NPC - Non-Player Character, a character who isn't a real player (eg shop owners where you can buy items).
28.AI - Artificial Intelligence, just like NPC's they are controlled by the computer (eg a robot).
27.MATS - Short for Materials, "I just got 25 MATS".
26.Glitch - A problem in the code (also knows as a bug), (eg you may "glitch" through a wall - could be said as you go through a wall).
25.Grinding - Playing for an insane amount of time in a game to earn reputation for ones avatar. It is mostly found in weaker games where player have to spend too much time to increase their strength or power.
24.Farming - You are gathering supplies in a game (eg collecting wood).
23.Easter Eggs - They are these awesome irrelevant features hidden by developers for the players to unlock. Most of the time they are totally unnecessary for the gameplay, but gamers do get an ego boost in finding them.
22.GG - Good Game, at the end of the match and you win and you say "gg" (shows your a good sport).
21.PvP - Player vs Player, a game where a player fights another player.
20.PvE - Player vs Environment, a game where a player fights an AI.
19.MOB - Monster or Beast, a bad guy in a game.
18.DPS - Damage Per Second, the amount of damage is caused a second (eg a sword may have a DPS of 20).
17.FFA - Free For All, everyman for himself.
16.Noob - a new player, probably bad at the game.
15.Camper - often frowned upon, sitting somewhere to wait for someone to pass.
14.Trolling - It’s the act of posting offensive statements to get someone’s instant reaction. Trolling is more often criticized by the gaming community.
13.Spammed - A person who is continuously pulling the trigger of the gun. Any killings made by them are more of a result of luck than any hardcore skills.
12.FTW - For The Win!
11.Owned - Used when you get badly beaten up in a game.
10.Ghosting - Is used when you are watching another player to get an advantage by overseeing the player’s moves.
9.Stream Sniping - When you watch a streamer to get an advantage on their location.
8.Aggro - When a MOB becomes agressive on a player.
7.FPS - First Person Shooter, you see through the players eyes.
6.Co-op - Co-op in video games are when two or more people are able to play the same game on the same system with each other just as long as you have an extra controller.
5.Demo - A demo is a free playable demonstration of a game that is intended to entice the player to purchase the full version.
4.Exploit - An exploit is when you find a glitch in a game engine and then abuse that glitch in order to further your own ends.
3.F2P - Free-to-play is a type of game, usually on the PC, that is free to access.
2.Hackers - Hackers are people that break a game. Most hackers break them with cheats. Many people regard cheating hackers as annoying because they have an unfair advantage against those people, and they have very little options to stop them.
1.Indie - Indie is a term which is used to describe games that were made by independent developers.