From wikipedia, for those who still dunno what certain words mean

gg - Short for "good game." Literally, it is just an expression to show that the players appreciate the game. May also mean "a good match"; or said out of courtesy during the game's end. However, it is often used to signal the end of a game or a point where the game cannot be won by a team. Increasingly, it is used to mean "nice try" or "I got you" by a player who has killed another player and is generally meant to taunt.

ggxx means gg multiplied ten times.

imba - Imbalanced. Used to indicate a hero, item or team that is considered inherently to be too strong.

lagger - A player who lags too much from the other players may be disconnected due to high lag times.

newbie, newb, noob,noobo,nubcake, nub,noobsauce, noobzor - An insult that attacks the player's skill. This insult implies that the player is new to the game. While not overtly insulting, players who are not new take offense because they believe they have more skill than someone playing the map for the first time. Newbie is less offensive than offshoots such as nublet or nubcake, which combines "noob" with "cupcake" for a more degrading effect.