religiousness vs religious

religiousness and religious both are nouns.

Word	Noun	Adjective	Verb	Adverb
religiousness	Yes	No	No	No
religious	Yes	Yes	No	No

religiousness (noun)	religious (noun)
piety by virtue of being devout	a member of a religious order who is bound by vows of poverty and chastity and obedience
the quality of being extremely conscientious

religiousness (adjective)	religious (adjective)
	having or showing belief in and reverence for a deity
	of or relating to clergy bound by monastic vows
	concerned with sacred matters or religion or the church
	extremely scrupulous and conscientious