From WoWWiki

Like all on-line games, World of Warcraft has developed rich but fairly cohesive glossary of slang terms to describe various things and occurences in the game. Some are specific to WoW, some are shared with many other MMORPGs.

If you wonder what a clothie, healbot or meat shield is, or what someone is up to when they're using a sword and board, or tanking and spanking something, your best place to look is the game terms category. If it doesn't have them all, it certainly has most.