bum vs tail end

bum and tail end both are nouns.

Word	Noun	Adjective	Verb	Adverb
bum	Yes	Yes	Yes	No
tail end	Yes	No	No	No

As nouns, bum and tail end are synonyms defined as:

bum (noun)	tail end (noun)
the fleshy part of the human body that you sit on	the fleshy part of the human body that you sit on
a vagrant	any projection that resembles the tail of an animal
a person who is deemed to be despicable or contemptible	the time of the last part of something
person who does no work

bum (adjective)	tail end (adjective)
of very poor quality; flimsy

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