young vs youngness

young and youngness both are nouns.

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

young (noun)	youngness (noun)
any immature animal	the opposite of oldness
young people collectively

young (adjective)	youngness (adjective)
(used of living things especially persons) in an early period of life or development or growth
(of crops) harvested at an early stage of development; before complete maturity
not tried or tested by experience
being in its early stage
suggestive of youth; vigorous and fresh