The French loan phrase faux pas (literally false step) is a noun meaning a social blunder or indiscretion. The plural form is spelled the same, but while the singular faux pas is pronounced foh-PAH, the plural faux pas is pronounced foh-PAHZ. Those are the French pronunciations, anyway.
Faux pas has been in English a long time, so there’s no need to italicize it in normal use. It doesn’t require a hyphen.
Among phone addicts, sporting an out-of-date device is a serious faux pas. [Economist]
Kevin Seraphin of the Wizards committed the unpardonable fashion faux pas of wearing his shorts backward Monday night against the Knicks in Madison Square Garden. [Washington Post]
These faux pas are not easily dismissed in a city that has long viewed itself as culturally superior to the rest of China. [Globe and Mail]
[W]hen I ordered the chocolate pithivier for dessert our waitress corrected my awful pronunciation with such grace that I barely noticed my faux pas. [New Zealand Herald]
This year’s MTV Video Music Awards show was full of fashion surprises and tragic faux pas. [Los Angeles Times]