obscenity vs rear end

obscenity and rear end both are nouns.

Word	Noun	Adjective	Verb	Adverb
obscenity	Yes	No	No	No
rear end	Yes	No	No	No

obscenity (noun)	rear end (noun)
an obscene act	the fleshy part of the human body that you sit on
the trait of behaving in an obscene manner
an offensive or indecent word or phrase