This is one of my favorite places that defines Noob
http://www.urbandictionary.com/define.php?term=noob
Defining 'Noob'
Contrary to the belief of many, a noob/n00b and a newbie/newb are not the same thing.
Newbs are those who are new to some task* and are very beginner at it, possibly a little overconfident about it, but they are willing to learn and fix their errors to move out of that stage.
n00bs, on the other hand, know little and
have no will to learn any more. They expect people to do the work for them and then expect to get praised about it, and make up a unique species of their own. It is the latter we will study in this guide so that the reader is prepared to encounter them in the wild if needed.
Noobs are often referred to as n00bs as a sign of disrespect toward them.
* Usually the topic at hand on an internet forum.