faux pas vs flub

faux pas and flub both are nouns.

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

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

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

faux pas (noun)	flub (noun)
a socially awkward or tactless act	an embarrassing mistake

faux pas (verb)	flub (verb)
	make a mess of, destroy or ruin