seniority vs junior

seniority and junior both are nouns.

Word	Noun	Adjective	Verb	Adverb
seniority	Yes	No	No	No
junior	Yes	Yes	No	No

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

seniority (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