senior vs ranking

senior and ranking both are nouns.

Word	Noun	Adjective	Verb	Adverb
senior	Yes	Yes	No	No
ranking	Yes	Yes	No	No

senior (noun)	ranking (noun)
an undergraduate student during the year preceding graduation	position on a scale in relation to others in status or rank or achievement
a person who is older than you are

senior (adjective)	ranking (adjective)
older; higher in rank; longer in length of tenure or service	having a higher rank
used of the fourth and final year in United States high school or college
advanced in years; (`aged' is pronounced as two syllables)