The term "n00b" is commonly confused with the term "newb".
A newb is short for a newbie, someone who is new to something.
A n00b is someone who, regardless of experience, is utterly crap at a game and will not take the advice of others.

These are generally big mouthed people who suffer from Delusions of Grandeur.

Upon being given advice, n00bs will either ignore it completely, or make a poor attempt at insulting the person giving them the advice.
A n00b will be the first person to point the finger at someone else if a mistake is made.
They are also the people that go around calling others n00bs for no particular reason.

90% of n00bs are unable to spell.

The word n00b is also commonly used in banter.
n00b: OMG, nyce shield lololol cn i buy plz?!?!?!?!?1
Player: Sorry, not for sale
n00b: OMG! n00b!

Person: Hey, can you plant the bomb please?
n00b: F U!!!!!!!

n00b: i r lyk 2 gd 4 u n00bs

*n00b charges one enemy and gets his ass handed to him*
n00b: wer th fk r u gys? i hd no bckup thr n i hd 2 fite 5 n00bs, bt thy killd me coz u ddnt hlp me. u r sht
by Jelal March 21, 2006
Get the mug
Get a n00b mug for your daughter Zora.
A pretentious term used by people who honestly believe using numbers to write words is still as cool now, as it was when the running man was considered a great dance move. Used to half-assedly insult a person who annoys the user without the necessary thought that usually goes into such a response.
In other words you don't actually need to think of a response as long as you just throw "n00b" into a five crap lines that usually break the rules of a forum anyway.

More often than not the user is often far worse than those they use it on.
*boy that guy's lame...I'm totally gonna tell him off.
"That'll learn 'em to goof off on UltimateSpaceFragOmniMercsElite.com This place for serious discussions on "fragging zombies in space with half naked women..."
*....now where's my penis pump and a my sweet-assed pic of Samus Aran bending over to tie her space boot.....*
by FlowersInMidgar September 28, 2006
Get the mug
Get a n00b mug for your barber Paul.
A n00b/noob is that annoying fat kid on xbox live that is yelling at everyone through the crappy mic and ends up with the lowest kill in the history of man, they are the ones that mess up a good match by teamkilling with flamethrowers or making your team lose the match by 1 point because they accidently walked off the edge of a cliff. Usually aged 8-14 and have nothing better to do than attempting internet greatness through the exessive and pointless use of crap lolcat pictures and animations that are so over used it makes you want to vomit (ps: i love lolcats with a passion but i am referring to the ones for example the cat with a sniper rather than the funny intellegent pictures)
n00b = suckish
cartman if he played online....n00b
by 310alucard March 03, 2009
Get the mug
Get a n00b mug for your boyfriend Trump.
Very annoying new user, refuses to learn basic board rules before signing up.
Man, that guy keeps disrespecting the vets. He's really acting like a n00b.
by Black Angel October 11, 2003
Get the mug
Get a n00b mug for your barber Helena.
A person who seems to have had a seizure and fallen on their keyboard, as every fucking word they type is grossly misspelled. Usually a fan of Hilary Duff, JoJo, and otherwise. Sometimes an Evanescence fan, so as to suggest their 't0tal raWknezz'.
Actual quote taken from the US.IMDB.com Hilary Duff boards:
Man she's too popular and too good! Amazing how many votes she gets for Mtv's TRL.
She's amazing, she can sing. It's a great song really GET IT. Her hits keep coming Why not, so yesterday, come clean, our lips our sealed and now FLY. She's the best, screw the rest! Out of those hits, 4 out 5 were number one's and So Yesterday was retired from the chart 'cause it was so good! F**k all you haters SHE'S NUMBER ONE, get use to it, she's the best! SO HOOOOOOOOOOOOOOOOOOOTTTTTTTTTTTTTTTTTTTTTT :)
Translation: I like Hilary Duff. She is an attractive young woman. I don't enjoy the music of other artists (because I'm a tree-hugging teenybopper pussy)
by Kitty September 12, 2004
Get the mug
Get a n00b mug for your sister-in-law Helena.
An extremely disparaging and offensive term for someone new to the game.

Similar to 'nigger'
Derek: Those fuckin n00bs are invading the game!

Davina: Oh my god, did you just use the n-word?!
by n00bian alliance August 26, 2007
Get the mug
Get a n00b mug for your cat José.
A retarded arrogant alcoholic fucktard who doesn't realize he is actually pressing a zero instead of an o. They are potentially dangerous, they might "pwn" or "rape" you while you are playing video games or on online forums. For safety precautions please wear a cup on your asshole when you play halo.
Nerd "zomg 1 pwn u n00b"
Hobbyist *puts cup over asshole*
by K1337 Jesus July 03, 2010
Get the mug
Get a n00b mug for your cousin Rihanna.