Dictionary.net

One who breaks horses; especially (Mil.), a noncommissioned officer in the British cavalry, whose duty is to assist the riding master.

One who breaks horses; especially (Mil.), a noncommissioned officer in the British cavalry, whose duty is to assist the riding master.

One who breaks horses to the saddle; Roughrider, colloquially, a soldier of the First United States Volunteer Cavalry in the Spanish-American War.

One skilled in rough and daring horseman ship, as on the plains of the western United States.