crumb vs bum

crumb and bum both are nouns.

Word	Noun	Adjective	Verb	Adverb
crumb	Yes	No	Yes	No
bum	Yes	Yes	Yes	No

As nouns, crumb and bum are synonyms defined as:

Other synonyms of crumb include dirty dog, git, lowlife, puke, rat, rotter, scum bag, scumbag, skunk, so-and-so, stinker, stinkpot.

crumb (noun)	bum (noun)
small piece of e.g. bread or cake	the fleshy part of the human body that you sit on
a person who is deemed to be despicable or contemptible	a vagrant
a very small quantity of something	a person who is deemed to be despicable or contemptible
	person who does no work

crumb (adjective)	bum (adjective)
	of very poor quality; flimsy

crumb (verb)	bum (verb)
remove crumbs from	ask for and get free; be a parasite
break into crumbs	be lazy or idle
coat with bread crumbs