rotter vs bum

rotter and bum both are nouns.

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

As nouns, rotter and bum are synonyms defined as:

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

rotter (noun)	bum (noun)
a person who is deemed to be despicable or contemptible	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

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

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