judge advocate vs staff officer

judge advocate and staff officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
judge advocate	Yes	No	No	No
staff officer	Yes	No	No	No

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

judge advocate: a staff officer serving as legal adviser to a military commander
staff officer: a commissioned officer assigned to a military commander's staff

judge advocate (noun)	staff officer (noun)
a staff officer serving as legal adviser to a military commander	a commissioned officer assigned to a military commander's staff
an officer assigned to the judge advocate general