Most of the answers are correct, I do have small additions:
Bumpmap: It's a kind of texture you have to make with special software. It creates the illusion of depth, but it doesn't alter the actual model of the object, it just alters the shading.
Noob: Not necessarily a person who's new, more a person who's annoying, most people described a Newbie, that's someone who's actually new and unfamiliar with the game.
Flaming [not flamming] is insulting another person over the internet, with hurting as main goal.
Bumping: Have you noticed the structure of the forums? Every board has got a list of "threads" the thread on top is the latest thread someone posted it. Bumping a thread means bringing it up in the list of threads.
-legal bump/illegal bump: You can legally bump in the market section, for instance if you're trying to sell something, but noone wants to buy. If you bump 24 hours after the last post, this is legal, if you bump before 24 hours have passed since the last post, this is illegal.
-Necroing:This is bumping a thread over 2 weeks old.