ass vs bum

ass and bum both are nouns.

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

As nouns, ass and bum are synonyms defined as:

ass (noun)	bum (noun)
slang for sexual intercourse	the fleshy part of the human body that you sit on
hardy and sure-footed animal smaller and with longer ears than the horse	a vagrant
the fleshy part of the human body that you sit on	a person who is deemed to be despicable or contemptible
a pompous fool	person who does no work

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

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