Reputation
Determines how NPCs will react to a player. Levels of reputation are Hated, Hostile, Unfriendly, Neutral, Friendly, Honored, Revered, and Exalted. Some items, quests, and recipes require a certain level of reputation to use or obtain. Reputation is gained and lost through killing NPCs and completing quests.
Res
Short for resurrect. Return to life after health has been reduced to zero.
Respawn
When a monster that has been killed appears again
Respec
Paying a trainer to unlearn all talents in order to reallocate talent points in a different way. The cost starts at 1 gold and increases to up to a maximum of 50 gold.
RFC
Ragefire Chasm, an instance in Orgrimmar
RFD
Razorfen Downs, an instance in the Barrens
RFK
Razorfen Kraul, an instance in the Barrens
RL
Real Life
Roll
Create new character. Also, generate a random number using the in-game loot rolling system, the /roll command, or dice.
Root
hold a target in place or an ability or spell that causes such an effect.
Scholo
Scholomance, an instance in Western Plaguelands
Seth Halls
Sethekk Halls, an Auchindoun instance in Terokkar Forest
SFK
Shadowfang Keep, an instance in Silverpine Forest
SH
Shattered Halls, a Hellfire Citadel instance in Hellfire Peninsula
Shard
Soul Shard, a reagent created by warlocks' Drain Soul spell. Also, refers to disenchanting an item.
Slabs
Shadow Labyrinth, an Auchindoun instance in Terokkar Forest
SM
Scarlet Monastery, a set of instances in Tristfal Glades
SMV
Shadowmoon Valley, a zone in the outlands
Snare
Reduce movement speed or an ability or spell that causes such an effect