horse cavalry vs trooper

horse cavalry and trooper both are nouns.

Word	Noun	Adjective	Verb	Adverb
horse cavalry	Yes	No	No	No
trooper	Yes	No	No	No

horse cavalry (noun)	trooper (noun)
an army unit mounted on horseback	a mounted police officer
troops trained to fight on horseback	a soldier in a motorized army unit
	a state police officer
	a soldier mounted on horseback