substantive vs substantival

substantive is a noun but substantival is not a noun.

Word	Noun	Adjective	Verb	Adverb
substantive	Yes	Yes	No	No
substantival	No	Yes	No	No

substantive (noun)	substantival (noun)
any word or group of words functioning as a noun

substantive (adjective)	substantival (adjective)
defining rights and duties as opposed to giving the rules by which rights and duties are established	of or relating to or having the nature or function of a substantive (i.e. a noun or noun equivalent)
of or relating to the real nature or essential elements of something
being on topic and prompting thought