navigator vs ship's officer

navigator and ship's officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
navigator	Yes	No	No	No
ship's officer	Yes	No	No	No

As nouns, ship's officer is a hypernym of navigator; that is, ship's officer is a word with a broader meaning than navigator:

navigator: the ship's officer in charge of navigation
ship's officer: a person authorized to serve in a position of authority on a vessel

Other hypernyms of navigator include officer.

navigator (noun)	ship's officer (noun)
in earlier times, a person who explored by ship	a person authorized to serve in a position of authority on a vessel
the member of an aircrew who is responsible for the aircraft's course
the ship's officer in charge of navigation