trooper vs police officer

trooper and police officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
trooper	Yes	No	No	No
police officer	Yes	No	No	No

As nouns, police officer is a hypernym of trooper; that is, police officer is a word with a broader meaning than trooper:

Other hypernyms of trooper include officer.

As nouns, police officer is a hypernym of trooper; that is, police officer is a word with a broader meaning than trooper:

Other hypernyms of trooper include officer.

trooper (noun)	police officer (noun)
a mounted police officer	a member of a police force
a soldier in a motorized army unit
a state police officer
a soldier mounted on horseback