grub vs bum

grub and bum both are nouns.

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

As verbs, grub and bum are synonyms defined as:

Other synonyms of grub include cadge, mooch, sponge.

grub (noun)	bum (noun)
a soft thick wormlike larva of certain beetles and other insects	the fleshy part of the human body that you sit on
informal terms for a meal	a vagrant
	a person who is deemed to be despicable or contemptible
	person who does no work

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

grub (verb)	bum (verb)
search about busily	ask for and get free; be a parasite
ask for and get free; be a parasite	be lazy or idle