An off tank (aka off-tank or offtank) is a player in a raid or party that concentrates on taking pressure off the main tank, usually by drawing off extra (usually weaker) mobs. Sometimes abbreviated to the acronym OT.

Also known as a secondary tank.

From The Way of the Punch Bag - A Guide to Tanking v2.0 from Allakhazam:

A player that can safely and effectively tank one enemy. Depending on the situation and composition of your group, this may apply to anything from paladins to rogues or range-spec hunters. Basically, if you are fighting more units than the main tank can handle (damage- or aggro-wise), an off tank needs to step in. As stated in the tips and tricks below, try to go for a target that isn't being attacked, it will be much easier for you to pull, and you will not need to attack it continuously to keep it locked on you.

Feral druids are well suited to play the role of off tank, as they can do damage for most of a fight/dungeon/raid and quickly switch forms to be effective tank, then switch back to doing damage when no longer needed. A warrior can easily play the role of off tank as well. Paladins mostly rely on being attacked to generate threat, as such they are not as well suited to off-tank unless done from the very beginning of a fight. In the case of multiple tanks in a raid group or instance, spec, gear, and class can be compared to determine tanking responsibilities (i.e. who will main tank and who will off tank specific encounters); like many aspects of raids, careful planning regarding tank strategy will reduce the confusion and lack of organization that lead to wipes.

There are two popular noun-definitions for the term "off tank".

  • A player character whose assigned task is to keep the attention (aggro) of any creature besides the group/raid's primary target.
  • A player character whose assigned task is to take over tanking a target in the event that the main tank can no longer do so. In this capacity, an off tank generates threat just like the main tank, but attempts to remain second on the threat list, not first. Ideally, if the main tank dies or loses aggro for any reason, the off tank can take over smoothly. In such cases, the off-tank usually becomes the main tank, at least temporarily.

This term is also used as a verb, meaning "to execute the tasks of either of the above roles".

See: Tank