flag rank vs paygrade

flag rank and paygrade both are nouns.

Word	Noun	Adjective	Verb	Adverb
flag rank	Yes	No	No	No
paygrade	Yes	No	No	No

As nouns, paygrade is a hypernym of flag rank; that is, paygrade is a word with a broader meaning than flag rank:

Other hypernyms of flag rank include military rank, military rating, rating.

flag rank (noun)	paygrade (noun)
the rank of a flag officer	rank in a military organization