Body:getAngularDamping
Gets the Angular damping of the Body

The angular damping is the ''rate of decrease of the angular velocity over time'': A spinning body with no damping and no external forces will continue spinning indefinitely. A spinning body with damping will gradually stop spinning.

Damping is not the same as friction - they can be modelled together. However, only damping is provided by Box2D (and LOVE).

Damping parameters should be between 0 and infinity, with 0 meaning no damping, and infinity meaning full damping. Normally you will use a damping value between 0 and 0.1.
damping = Body:getAngularDamping()
damping number The value of the angular damping.