If you're like me you have a handle on the vocabulary used in an mmo, such as but not limited to; threat, aggro, tank, dps, mobs, kiting, etc. However several other terms are used in the social setting of an mmo.
1) In Reference to Players
Newbie vs Noob vs Lowbie
A)Newbie-The newbie is considered to be a new player to the genre or the game itself, These people can be spotted a mile away, with wrong gear(casters with melee dps gear, tanks with healing items) but can be taught, or will learn generally.
B)The Noob - A more derrogitory term for a newbie, or a person who claims to understand game mechanics but still does not live up to the expectations s/he sets. Also used to describe a class that is easy to play(see faceroll).
C)Lowbie/Alt/Reroll/Twink - Lowbie/Reroll are used to describe characters that are started fromscratch that are played by experienced players. An alt or Alternative Character is a character who can be supported by a Higher level character, or main. A twink is a low level character whois equipped with weapons and armor that would not be available easily at the current level of the twink.
2) On the field against other players
Faceroll Class - A term that indicates the class is so easy to play that you need only to bind certain spells to the keyboard and roll your face across it to activate the keys and still be well above average.
Steamrolling - Like an unstoppable force going against a very movable object a group of players annhilate the opposing force.
3) In /ooc /2 /yell or the forums terms to be aware of.
Troll - Besides a MoB or a player race this is someone who intentionally provokes people intorguements/shouting/harassment for their own amusement
Vocal Minority - A common buzzword that is used to describe an active player demographic in, usually derrogitory sense (i.e. A few Class X couldn't handle Class Y in pvp so their Vocal Minority complained a lot and Class Y got nerfed to hell)
L2P - Learn To Play <insert what you need to learn to play here>, a shorter version of this is L2<insert>
Edited for format