introversive vs introversion

introversive is not a noun while introversion is a noun.

Word	Noun	Adjective	Verb	Adverb
introversive	No	Yes	No	No
introversion	Yes	No	No	No

introversive (noun)	introversion (noun)
	(psychology) an introverted disposition; concern with one's own thoughts and feelings
	the folding in of an outer layer so as to form a pocket in the surface
	the condition of being folded inward or sheathed

introversive (adjective)	introversion (adjective)
directed inward; marked by interest in yourself or concerned with inner feelings