Newbie

The general term "newbie" means someone new to the game. The connotations of this differ depending on the context and the circumstance:
 * New and inexperienced: A player that's new will say "I'm a newbie" to imply he/she is new at the game or the area they are in. A veteran might say: "Ok, any newbies here?" to mean, any players who have never before done the task the party is about to do.
 * Ignorant, unaware or clueless: A player who carelessly aggros a group when the party was not ready or walks into a set of traps and kills himself would cause messages of "Are you a noob?!!!" from other party members.
 * Obnoxious, uncooperative or does not listen: Many new players try to cover up their ignorance (because of the little tolerance shown to ignorance as seen above) by pretending to know what they are doing and taking brash actions while refusing to heed advice/warnings from veterans. When such players bring about harm to the party they will often stir such responses as "You're a ing noob!!"

There are many variants, far too many to list here. Some people use "leetspeak", for (n00b) or add suffixes to the end, (nooblet, noob sauce etc) these variants aren't as well used, but you will see them being used.

Also see Wikipedia's newbie article.