syncretism vs syncretistical

syncretism is a noun but syncretistical is not a noun.

Word	Noun	Adjective	Verb	Adverb
syncretism	Yes	No	No	No
syncretistical	No	Yes	No	No

syncretism (noun)	syncretistical (noun)
the fusion of originally different inflected forms (resulting in a reduction in the use of inflections)
the union (or attempted fusion) of different systems of thought or belief (especially in religion or philosophy)

syncretism (adjective)	syncretistical (adjective)
	of or characterized by syncretism
	relating to a historical tendency for a language to reduce its use of inflections