(Irregular plural: highwaymen).
One who robs on the public road; a highway robber.
In English history, a thief on horseback who robbed travelers on the highway (those who did so on foot were known as footpads). Highwaymen continued to flourish well into the 19th century.
With the development of regular coach services in the 17th and 18th centuries, the highwaymen's activities became notorious, and the Bow Street runners (see police) were organized to suppress them.