ne'er-do-well vs bum

ne'er-do-well and bum both are nouns.

Word	Noun	Adjective	Verb	Adverb
ne'er-do-well	Yes	No	No	No
bum	Yes	Yes	Yes	No

As nouns, bum is a hypernym of ne'er-do-well; that is, bum is a word with a broader meaning than ne'er-do-well:

Other hypernyms of ne'er-do-well include do-nothing, idler, layabout, loafer.

ne'er-do-well (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

ne'er-do-well (adjective)	bum (adjective)
	of very poor quality; flimsy

ne'er-do-well (verb)	bum (verb)
	ask for and get free; be a parasite
	be lazy or idle