juvenile person vs mortal

juvenile person and mortal both are nouns.

Word	Noun	Adjective	Verb	Adverb
juvenile person	Yes	No	No	No
mortal	Yes	Yes	No	No

As nouns, mortal is a hypernym of juvenile person; that is, mortal is a word with a broader meaning than juvenile person:

juvenile person: a young person, not fully developed
mortal: a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential

Other hypernyms of juvenile person include individual, person, somebody, someone, soul.

juvenile person (noun)	mortal (noun)
a young person, not fully developed	a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential

juvenile person (adjective)	mortal (adjective)
	subject to death
	unrelenting and deadly
	involving loss of divine grace or spiritual death
	causing or capable of causing death