good-for-naught vs bum

good-for-naught and bum both are nouns.

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

As nouns, bum is a hypernym of good-for-naught; that is, bum is a word with a broader meaning than good-for-naught:

Other hypernyms of good-for-naught include do-nothing, idler, layabout, loafer.

good-for-naught (noun)	bum (noun)
an idle worthless person	the fleshy part of the human body that you sit on
	a vagrant
	a person who is deemed to be despicable or contemptible
	person who does no work

good-for-naught (adjective)	bum (adjective)
without merit; of little or no value or use	of very poor quality; flimsy

good-for-naught (verb)	bum (verb)
	ask for and get free; be a parasite
	be lazy or idle