introversion vs introversive

introversion is a noun but introversive is not a noun.

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

introversion (noun)	introversive (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

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