A horseman is someone who rides horses for work or pleasure.
You might hear people talking about horsemen as cowboys or horse riders in competitions. In everyday language, though, a horseman can simply be someone who loves to ride and take care of their horses at home. If you've ever seen a person with a big horse farm, they're probably a horseman too.
How common is "horseman"?
Word horseman is considered rare in modern English. It appears most frequently in fiction texts and less often in other writings.
Definitions
noun
A man who rides a horse.
A soldier on horseback.
A man skilled in horsemanship.
A man in charge of work horses.
A swift-running land crab of the genus Ocypoda, living on the coast of Brazil and the West Indies.