adulthood vs parenthood

adulthood and parenthood both are nouns.

Word	Noun	Adjective	Verb	Adverb
adulthood	Yes	No	No	No
parenthood	Yes	No	No	No

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

adulthood: the state (and responsibilities) of a person who has attained maturity
parenthood: the state of being a parent

Other hyponyms of adulthood include manhood, parentage, muliebrity, womanhood.

adulthood (noun)	parenthood (noun)
the state (and responsibilities) of a person who has attained maturity	the state of being a parent
the period of time in your life after your physical growth has stopped and you are fully developed