youngness vs puerility

youngness and puerility both are nouns.

Word	Noun	Adjective	Verb	Adverb
youngness	Yes	No	No	No
puerility	Yes	No	No	No

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

Other hyponyms of youngness include juvenility, youth, youthfulness, childishness.

youngness (noun)	puerility (noun)
the opposite of oldness	a property characteristic of a child
	the state of a child between infancy and adolescence