good-for-naught vs sorry

good-for-naught is a noun but sorry is not a noun.

Word	Noun	Adjective	Verb	Adverb
good-for-naught	Yes	Yes	No	No
sorry	No	Yes	No	No

As adjectives, good-for-naught and sorry are synonyms defined as:

Other synonyms of good-for-naught include good-for-nothing, meritless, no-account, no-count, no-good.

good-for-naught (noun)	sorry (noun)
an idle worthless person

good-for-naught (adjective)	sorry (adjective)
without merit; of little or no value or use	feeling or expressing regret or sorrow or a sense of loss over something done or undone
	bad; unfortunate
	causing dejection
	without merit; of little or no value or use