dirty word vs scatology

dirty word and scatology both are nouns.

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

As nouns, scatology is a hyponym of dirty word; that is, scatology is a word with a more specific, narrower meaning than dirty word:

dirty word: an offensive or indecent word or phrase
scatology: a preoccupation with obscenity (especially that dealing with excrement or excretory functions)

Other hyponyms of dirty word include bawdry, bawdy.

dirty word (noun)	scatology (noun)
an offensive or indecent word or phrase	(medicine) the chemical analysis of excrement (for medical diagnosis or for paleontological purposes)
a word that is considered to be unmentionable	a preoccupation with obscenity (especially that dealing with excrement or excretory functions)