conclusive vs decisiveness

conclusive is not a noun while decisiveness is a noun.

Word	Noun	Adjective	Verb	Adverb
conclusive	No	Yes	No	No
decisiveness	Yes	No	No	No

conclusive (noun)	decisiveness (noun)
	the trait of resoluteness as evidenced by firmness of character or purpose
	the quality of being final or definitely settled

conclusive (adjective)	decisiveness (adjective)
forming an end or termination; especially putting an end to doubt or question