The term 'moderate gaits' refers to the three gaits of a horse that are considered to be the most comfortable for riding: walk, trot, and canter. The five-letter solution to this crossword is 'TROTS, ' which is the name of the second of these gaits. The trot is a two-beat gait in which the horse's legs move in diagonal pairs, with the front and hind legs on one side moving together. It is faster than the walk, but slower than the canter, and is often used for long-distance riding.