A clamp on the effective world-space angular velocity that is passed to the simulation. Units are radian/s, so a value of about 6.0 is one rotation per second. The default value effectively means "unlimited". You would reduce this (and Max Angular Acceleration) to limit how much bodies fly out when the actor spins on the spot. This is especially useful if you have characters that can rotate very quickly and you would probably want values around or less than 10 in this case.