officer vs trooper

officer and trooper both are nouns.

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

As nouns, trooper is a hyponym of officer; that is, trooper is a word with a more specific, narrower meaning than officer:

officer (noun)	trooper (noun)
a member of a police force	a mounted police officer
someone who is appointed or elected to an office and who holds a position of trust	a soldier in a motorized army unit
any person in the armed services who holds a position of authority or command	a state police officer
a person authorized to serve in a position of authority on a vessel	a soldier mounted on horseback

officer (verb)	trooper (verb)
direct or command as an officer