1) Equestrian 2) French word used in English 3) Horseback rider 4) Horseman 5) Postillion 1) Postillion 
one who guides a horse-driven coach by riding on the left-hand lead horse.
Jockey.
A postilion (or postillion, occasionally Anglicised to `post-boy`) rider was the driver of a horse-drawn coach or post chaise, mounted on one of the drawing horses. By contrast, a coachman would be mounted on the vehicle along with the passengers. Postilion riders normally rode the left (or `near`) horse of a pair because horses usually were t...
someone who guides posthorses
• (n.) One who rides and guides the first pair of horses of a coach or post chaise; also, one who rides one of the horses when one pair only is used.
Pos·til'ion noun [ French postillon , Italian postiglione , from posta post. See Post a postman.] One who rides and guides the first pair of horses of a coach or post chaise; also, one who rides one of the horses when one pair only is used. [ Written also postillion ...
Jockey.
[n] - someone who rides the near horse of a pair in order to guide the horses pulling a carriage (especially a carriage without a coachman)
postillion noun someone who rides the near horse of a pair in order to guide the horses pulling a carriage (especially a carriage without a coachman)