army officer vs officer

army officer and officer both are nouns.

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

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

army officer: an officer in the armed forces
officer: any person in the armed services who holds a position of authority or command

Other hypernyms of army officer include military officer.

army officer (noun)	officer (noun)
an officer in the armed forces	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

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