juvenile vs youth

juvenile and youth both are nouns.

Word	Noun	Adjective	Verb	Adverb
juvenile	Yes	Yes	No	No
youth	Yes	No	No	No

As nouns, youth is a hyponym of juvenile; that is, youth is a word with a more specific, narrower meaning than juvenile:

juvenile (noun)	youth (noun)
a young person, not fully developed	the freshness and vitality characteristic of a young person
	young people collectively
	a young person (especially a young man or boy)
	early maturity; the state of being young or immature or inexperienced
	the time of life between childhood and maturity
	an early period of development

juvenile (adjective)	youth (adjective)
of or relating to or characteristic of or appropriate for children or young people
displaying or suggesting a lack of maturity