higher rank vs junior

higher rank and junior both are nouns.

Word	Noun	Adjective	Verb	Adverb
higher rank	Yes	No	No	No
junior	Yes	Yes	No	No

higher rank (noun)	junior (noun)
higher rank than that of others especially by reason of longer service	the younger of two persons
	a third-year undergraduate
	term of address for a disrespectful and annoying male

higher rank (adjective)	junior (adjective)
	younger; lower in rank; shorter in length of tenure or service
	used of the third or next to final year in United States high school or college
	including or intended for youthful persons