bum vs crumb

bum and crumb both are nouns.

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

As nouns, bum and crumb are synonyms defined as:

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

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

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

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