paperbacked vs paperback

paperbacked is not a noun while paperback is a noun.

Word	Noun	Adjective	Verb	Adverb
paperbacked	No	Yes	No	No
paperback	Yes	Yes	No	No

As adjectives, paperbacked and paperback are synonyms defined as:

paperbacked (noun)	paperback (noun)
	a book with paper covers

paperbacked (adjective)	paperback (adjective)
(of books) having a flexible binding	(of books) having a flexible binding