FO vs commissioned military officer

FO and commissioned military officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
FO	Yes	No	No	No
commissioned military officer	Yes	No	No	No

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

FO: an officer holding the rank of major or lieutenant colonel or colonel
commissioned military officer: a commissioned officer in the Army or Air Force or Marine Corps

FO (noun)	commissioned military officer (noun)
an officer holding the rank of major or lieutenant colonel or colonel	a commissioned officer in the Army or Air Force or Marine Corps