One whose employment is to break or train horses.(noun)
The Century Dictionary (Public Domain)
Use "horse-breaker" in a sentence
"Having been challenged by the blacksmith, in a spirit of banter, to attempt the breaking of a certain incorrigible colt, he succeeded so signally as to earn quite a reputation as a horse-breaker."
"My Father-in-Law, a Montana rancher and horse-breaker born in 1922, once watched the Running of the Bulls in Pamplona with me."
"For every art aims at this, that the thing which has been made should be adapted to the work for which it has been made; and both the vine-planter who looks after the vine, and the horse-breaker, and he who trains the dog, seek this end."