Pro: Being well rounded for starters. For someone to be considered pro on an official level they have to know how to handle high-tier MVP as well as WoE. PvP rarely plays into that. Most PvP'ers tend to lack basic skills and are just in it for e-peen. Something else that figures into someone being pro in my mind is having the ability to work with the gears you have. Even if those gears happen to be absolute crap (USRC** situation comes to mind). You can be pro with a specific class and blow with every other class.
Noob: someone who can't even handle their own class/character. I really don't understand how anyone can reach 99/70 without knowing how to play a class. Especially if a person actually leveled it. I've also seen some of the DUMBEST uses of cards in the world. Prime example. On officials this dumb _______ put a hydra card in a +7 giant axe. Racial/prop cards don't effect CT damage. Only atk cards (and not +% atk) effect CT. Did I mention said axe at that refine rate is hella hard to get? I liken it to someone putting an MVP (for weapon) card into a knife [4].
Another thing that would make someone noob IMO is a player who's been playin for years yet doesn't understand the game mechanics. Simple things like how size card multipliers work in weapons. I've even run into players who've been playing for years yet still don't seem to comprehend what elements effect other elements.
**USRC is United States Ragnarok Competition. It's an official competition that's the qualifier for the world comp. You can't use any gear you want, you're limited to specific gears available. You're also limited to how much zeny you have to purchase those gears and supplies from GM set NPCs. If you're curious to see what kind of limitations there are check out my screenshots here:
http://s736.photobucket.com/albums/xx10/...RC%202010/
Note that I did condense what's available in the shops into sep images. Too much to upload otherwise. This makes for easy viewing.