noob, sometimes spelled n00b, is not to be confused with newb, although they sound the same. both terms are most commonly associated with videogames. a newb is short for a newbie, a term for a new or inexperienced player who is currently bumbling and unskilled but is an ok person and is open to help and advice from other players and may improve in the future.
Noobs are best described as narcissistic, disillusioned morons. They think that they are extremely skilled at whatever game they happen to be playing and can 'pwn' (destroy in a particularly embarassing fashion) their opponents/enemies when in reality they really really suck and drag down the experiences of all who are involved.
Noobs are self-destructing people. They typically alienate everyone around them by bringing with them irritating attitudes of superiority. They also tend to make surprisingly stupid mistakes, going above and beyond the call of duty to fail in their tasks in remarkably spectacular ways. Things like running blindly into waves of enemies, jumping off cliffs to find treasure even though there is obviously nothing there, and (possible in some situations) killing their teammates by accident in dozens of situations in a sitting, are just the tip of the iceberg. Whenever challenged about their evident stupidity, noobs consistently blame others and engage the annoying defense mechanism of posting nonsensical hate-inspired walls of text into public online chat channels.
Needless to say, noobs' behavior patterns are easily recognized and almost always get them kicked out of whatever group they are in. Noobs are to be avoided at all costs because they are all whirling dervishes of chaos and idiocy who inadvertently obliterate all traces of cohesiveness in a group from within.