throwback vs regressive

throwback is a noun but regressive is not a noun.

Word	Noun	Adjective	Verb	Adverb
throwback	Yes	Yes	No	No
regressive	No	Yes	No	No

throwback (noun)	regressive (noun)
a reappearance of an earlier characteristic
an organism that has the characteristics of a more primitive type of that organism

throwback (adjective)	regressive (adjective)
characteristic of an atavist	opposing progress; returning to a former less advanced state
	(of taxes) adjusted so that the rate decreases as the amount of income increases