seniority vs senior status

seniority and senior status both are nouns.

Word	Noun	Adjective	Verb	Adverb
seniority	Yes	No	No	No
senior status	Yes	No	No	No

As nouns, seniority and senior status are synonyms defined as:

seniority and senior status: higher rank than that of others especially by reason of longer service

Other synonyms of seniority include higher rank, higher status.

seniority (noun)	senior status (noun)
the property of being long-lived	higher rank than that of others especially by reason of longer service
higher rank than that of others especially by reason of longer service