The crossword solution for the term 'Restrained, as a horse' is 'Reined'. Reining is a western riding competition where the horse is asked to perform a series of maneuvers such as circles, spins, and stops. The horse is guided by the rider using reins, which are leather straps attached to the bit in the horse's mouth. The reins are used to control the horse's speed and direction, and to communicate with the horse. Reining is an important part of horsemanship and is used to train horses for other disciplines such as dressage and jumping.