A noob is someone who is either 1.) A person who is a new player to a game and/or online community. 2.) A player of a game/member of an online community that is highly disruptive to said game/community due to either asking stupid questions, inciting single-person uprisings against the established society, harassing other players/members, or spamming.
1. "That noob just registered five minutes ago!"
2. "Joe is such a noob, he's trying to get the administrator banned again!"