noun a mounted soldier; a cavalryman.
2. horseman ·noun a rider on horseback; one skilled in the management of horses; a mounted man.
3. horseman ·noun a west indian fish of the genus eques, as the light-horseman (e. lanceolatus).
4. horseman ·noun a land crab of the genus ocypoda, living on the coast of brazil and the west indies, noted for running very swiftly.