abbrievated form of noob with a humourous tone. However, it is NOT like Newbie or Newb, these have the meaning
New to the game or Low Level in RPG games. Many wrongly think all that begins with N means the same thing, ffs !
Omg, that nub just fucked up the whole mission by aggroing 101 mobs!
nub picks up worthless item when he could have gotten a sword of megapwnage