officer vs ship's officer

officer and ship's officer both are nouns.

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

As nouns, officer and ship's officer are synonyms defined as:

officer and ship's officer: a person authorized to serve in a position of authority on a vessel

officer (noun)	ship's officer (noun)
a member of a police force	a person authorized to serve in a position of authority on a vessel
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

officer (verb)	ship's officer (verb)
direct or command as an officer