1. an embarrassing or impolite error made in a social situation
make a bit of a faux pas
'Faux pas' is a French term used in English to refer to a social or behavioural mistake - usually, one which causes embarrassment or causes offence. You can 'make a faux pas', or 'commit a faux pas'. This is a polite term used in both social and professional contexts, but it's not very popular and may sound a little pretentious in everyday conversation.