I have put together a compile of gamer terminology/slang often used during game chat into a list. If there is anything i have left out please feel free to leave it in the comment section and I'll be happy to add them to the list as soon as i can.
Character Roles (Roles)
Game genre (Genre)
In game chat abbreviations (Chat)
360: Xbox 360
2h, 2-h: two handed weapon
AI: "Artificial Intelligence"
AS: "Attack Speed"
AD: "Attack Damage"
AFK: "Away From Keyboard"
AA: "alternate abilities"
Aura: An AOE that usually stays active for a set length of time.
Agro, Aggro: when a player has the attention of, and is being attacked by an NPC.
AH: "auction house"
APM: "actions per minute"
Alpha: Early phase of testing the game software.
Alt: "Alternate character". Characters created in addition to a players main character.
Avatar: The game characters model or picture used to represent a player.
ADD: another NPC who comes to fight the player(s).
BG: "Bad Game"
BIO: "restroom break"
BAF: "brought a friend" or "bring a friend"
BO: "build order"
Bot: A players character being controlled/played by an external program.
Buffs: Spells that enhance states or abilities of a character.
Beta: Second phase of testing the game prior to its release.
Open beta: open for anyone to test.
Closed beta: available only to the selected few to test.
Bug: Faults in the programming causing unintended effects.
BOP: "Binds on pick up"
BOE: "Binds when equipped"
Carry: (Role) A character or player who has the ability to pull most of the weight of their team and take them to victory.
Crash: When a console/computer stops responding.
CTF: "Capture the flag"
CC: "crowd control"
Cap (it): that act of capturing the enemy's flag
Camping: Killing a target repeatedly every time it reappears at the respawn point.
Coop, Co-op: Cooperative play, where two or more players can work together through a games story mode, missions, etc...
Creeping: In RTS's, its the act of taking out NPC opponents to level up ones own units.
Choke: In RTS's its the act of preventing your opponent from expanding their base and from gaining more resources.
Ding!: leveled up
DC: "disconnected from server"
Dood, d00d: "dude"
DS: Nintendo Dual Screen
DDR: Dance Dance Revolution
DPS: "Damage per second"
DOT: "Damage over time"
Debuff: A spell that removes buffs
DLC: "Downloadable Content"
E3: Electronic Entertainment Expo.
Exp: "experience points"
EFC: "Enemy Flag Carrier"
Expansion Pack: Additional content for a game created by the developer.
Expansion: In RTS games, its the building of new smaller base build elsewhere on the map, often use to gather more resource or control over a section of the playing field.
Easter Egg: an intentionally hidden cheat or hidden content in video game,also confirmed as ''Secret.''
FTW: "For the win"
FTL: "For the lose"
FvF: "Faction versus Faction"
FC: "Flag carrier"
FH: "Flag holder"
Farming: Doing the something over and over again to achieve a goal.
FF# (EX: FFII, FFIII, FFX, FFX-2, etc...): a game from the Final Fantasy series
FOV: "field of view"
FPS: First person shooter (game genre). or "Frames-per-second".
Frag'n'Tag, Frag Tag: (PG version) A saying commonly used in Gears of War when a player places a grenade on an opponent and hops away.
GG: "good game"
GJ: "good job"
GL: "Good luck", "Guild Leader"
GT: "ground target"
Gibbing: a term used in reference to making certain someone cannot be revived by pumping their remains full of lead. This is only used in FPS games where people can actually be revived by other players.
Gibs: a term used in reference to... gore present after killing someone (flying body parts).
Gank: To be ganked is to have your character killed by way higher level player.
GBA: GameBoy Advance
GDC: Game Developers Conference
Gold, Gone gold: (General software term) The final version of software has been sent to the manufacturers for printing and publishing, which usually means it will be released soon. All future updates will be made though patches.
GTA, GTA:VC and GTA:SA: Grand Theft Auto, GTA:Vice City and GTA:San Andreas
Grind: Performing mindlessly repetitive tasks in order to level up or proceed in the game.
GTG: "good to go" or "Got to go"
GvG: "guild versus guild"
GRAW: Tom Clancys Ghost Recon Advanced Warfighter
GOW: God of War, or Gears of War
GeOW: Gears of War
GM: "Game Master" or "Guild Master"
Gimp: A character that is very weak/useless, either because of the player, or game company has screwed up the game balance.
HL/HL2: Half-Life / Half-Life 2.
HP: "Hit points"
HF: "Have Fun"
HUD: Heads-up display
Hitscan: refers to a specific type of aiming with weaponry that has no delay. This means said weapon is not projectile-based, but impacts instantly upon it's target, such as most sniper rifles in FPS games.
Healer: (Role) A Character/player who has the ability to replenish lost health.
Harassing: in an RTS, refers to the act of disrupting the opponents play by taking small amounts of units in to attack their supply lines and/or damage their base.
IRL: "In Real Life"
IAMF: "It's all my fault"
Instanced: A zone that is created by the server specifically for a single player or group of players, or for a limited number of players.
joo, j00: "you"
KS: "kill-stealing", "Kill steal"
KOS: "Kill on sight" or "Kill on spot"
Kite: a particular combat technique, attacking then running away, repeat until enemy is dead.
Lag: Time delay between sending a command to the game and your character actually performing the action. Frequently cursed when the time delay is longer than expected.
Lagger: Someone with a slow connection, or who is late to react.
LAN: "local area network"
Leet, 1337, l33t, 31337, 133+: "Elite"
LFG: "Looking for group"
LFP: "Looking for party/person/player"
LFS: "looking for a squad"
LFT: "looking for a team"
L2P, LTP: "learn to play"
LoD: "Level of Detail"
l00t, lewt, loot: treasure often found in chests or that a monster drops
LM: "loot master"
LoS: "Line of sight"
LOP: "low on power"
LOM: "low on mana"
Mana, MP: Mana or Magic Points. Spells often have an MP cost with higher spells costing more points. Commonly used in RPGs.
MM: "Mass Marine", a strategy commonly used in StarCraft
MMO: (Game Genre) Massively Multiplayer Online
MMORPG: (Game Genre) Massively Multiplayer Online Role Playing Game
Mob: NPC enemy
Mod: File modifications/patches. or Moderator.
Main: Your most played, highest level, or first created character.
Micro: refers to the act of swiftly commanding all your forces at all times.
macro: refers to the overall game plan, including economy.
MUD: Multi-User Dungeon
MT: "Mistell" or "Main tank"
Mia: "Missing in action"
Noob, n00b, nub: Newbie, new person, inexperienced person (often derogatory).
Ninja Looting: grabbing loot from a slain monster, chest, etc., that you don't have a right to grab, or that you didn't earn, or that you don't need.
N64: Nintendo 64
NES: Nintendo Entertainment System
NS: "nice shot"
NJ: "nice job"
Nerf: when the game maker reduces the relative power of a given character
Owned, OWN, OWND: Lost the game by a large margin.
OOM: "out of mana"
OTW: "on the way"
OMW: "on my way"
OOE: "out of endurance"
OOC: "out of concentration", "out of character"
OOP: "out of power"
OTM: "on the move"
OP: "Over Powerful"
PUG: "Pick-Up Group" a group of random players playing together.
Patch: (General software term) Files distributed by the developer after a product is released that will change the software when they are installed. These are usually used to fix bugs and security issues but can be used to add functionality.
PvM: Player versus Monster
PvE: Player versus Environment/enemy
pulling: refers to the act of trying to single out a monster by attracting it using long-ranged attacks.
p2p: "Pay to Play"
PL: "power level"
PC: "Player Character" or "Personal Computer"
Platform: Console type required to play the game.
PK, PKer: "Player Killer"
PvP: Player versus Player
PS1, PS2, PS3, PSP: PlayStation One, Two, Three, Portable.
PCW: "practice clan war", which refers to a match played between two clans that does not count for any competitions, but is solely intended for practice purposes.
Rush: a term used in reference to players who attack very early in the game to try and kill the opponent before the game has even begun.
RPG: (Game Genre) Role-playing game
RTS: (Game Genre) Real-time strategy
ROG: "random object generator"
Sandbox Game: player is free to go wherever they like within the game environment. These games are also referred to as free roam games.
Sens: sensitivity, referring to mouse sensitivity settings.
spam: to repeat something over and over again rapidly.
spray and pray: another means of referring to spam which is specific to weapons that are easily used to spray bullets in quick succession, such as machine guns.
Spree: refers to killing several opponents in a row.
Sim: (Game Genre) "Simulation". Also refers to any character in The Sims franchise.
SP: "Gameboy advance SP", or "Single player"
Spawn: A place where an NPC or MOB appears in the game world
Tank: (Role) A character/player who can take a large amount of damage before being taken down.
Twink: A low-level character wearing gear that is far superior to what they could normally obtain on their own.
Toon: "Cartoon", an online game character.
TBS: (Game Genre) "Turn-Based Strategy"
TPS: (Game Genre) "Third-person shooter"
TS: " Teamspeak", a downloadable voice communication software.
Teching: In RTS games, the act of building minor forces in the beginning, and researching lots of advancements in order to make superior units.
Turtle: A strategy using massive defense at a base.
TOS: "Terms of Service"
Tea-bagging: Also known as corpse-humping, is a slang term in video games when after a player has slain another player or NPC, they move their character over the dead character's body and crouch up and down repeatedly, adding a humiliating, and often humorous, factor to the character's death.
UI: "User Interface"
Vent: " Ventrilo", a downloadable voice communication software.
WTG: "way to go!"
WTS: "Want to Sell"
WTT: "Want to Trade"
WTB: "Want to Buy"
WoW: World of Warcraft
WRU: "Where are you?"
XP: "Experience Points"
XBL: "Xbox Live"
YT: "You there?"
Zerg: No tactics, just pure overwhelming of the opponents with numbers.
Squidoo. "Glossary of Online Gaming Acronyms, Abbreviations and Slang"
"Rei's Random Guide to MMP Gaming Terms"
Inventors Spot. "Your Guide to Video Game Terminology: Advanced"