good-for-naught vs ne'er-do-well

good-for-naught and ne'er-do-well both are nouns.

Word	Noun	Adjective	Verb	Adverb
good-for-naught	Yes	Yes	No	No
ne'er-do-well	Yes	No	No	No

As nouns, good-for-naught and ne'er-do-well are synonyms defined as:

Other synonyms of good-for-naught include goldbrick, good-for-nothing, goof-off, no-account.

good-for-naught (noun)	ne'er-do-well (noun)
an idle worthless person	an idle worthless person

good-for-naught (adjective)	ne'er-do-well (adjective)
without merit; of little or no value or use