police captain vs officer

police captain and officer both are nouns.

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

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

Other hypernyms of police captain include police officer.

police captain (noun)	officer (noun)
a policeman in charge of a precinct	a member of a police force
	someone who is appointed or elected to an office and who holds a position of trust
	any person in the armed services who holds a position of authority or command
	a person authorized to serve in a position of authority on a vessel

police captain (verb)	officer (verb)
	direct or command as an officer