faux pas vs pratfall

faux pas and pratfall both are nouns.

Word	Noun	Adjective	Verb	Adverb
faux pas	Yes	No	No	No
pratfall	Yes	No	No	No

As nouns, pratfall is a hypernym of faux pas; that is, pratfall is a word with a broader meaning than faux pas:

Other hypernyms of faux pas include bloomer, blooper, blunder, boner, boo-boo, botch, bungle, flub, foul-up, fuckup.

faux pas (noun)	pratfall (noun)
a socially awkward or tactless act	an embarrassing mistake
	a fall onto your buttocks