postilion vs equestrian

postilion and equestrian both are nouns.

Word	Noun	Adjective	Verb	Adverb
postilion	Yes	No	No	No
equestrian	Yes	Yes	No	No

As nouns, equestrian is a hypernym of postilion; that is, equestrian is a word with a broader meaning than postilion:

postilion: someone who rides the near horse of a pair in order to guide the horses pulling a carriage (especially a carriage without a coachman)
equestrian: a person skilled in equitation

Other hypernyms of postilion include horseback rider.

postilion (noun)	equestrian (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)	a person skilled in equitation

postilion (adjective)	equestrian (adjective)
	of or relating to or featuring horseback riding
	of or relating to or composed of knights