dirty word vs obscenity

dirty word and obscenity both are nouns.

Word	Noun	Adjective	Verb	Adverb
dirty word	Yes	No	No	No
obscenity	Yes	No	No	No

As nouns, dirty word and obscenity are synonyms defined as:

Other synonyms of dirty word include filth, smut, vulgarism.

dirty word (noun)	obscenity (noun)
an offensive or indecent word or phrase	an obscene act
a word that is considered to be unmentionable	the trait of behaving in an obscene manner
	an offensive or indecent word or phrase