junior vs young

junior and young both are nouns.

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

junior (noun)	young (noun)
the younger of two persons	any immature animal
a third-year undergraduate	young people collectively
term of address for a disrespectful and annoying male

junior (adjective)	young (adjective)
younger; lower in rank; shorter in length of tenure or service	(used of living things especially persons) in an early period of life or development or growth
used of the third or next to final year in United States high school or college	(of crops) harvested at an early stage of development; before complete maturity
including or intended for youthful persons	not tried or tested by experience
	being in its early stage
	suggestive of youth; vigorous and fresh