faux pas

An embarrassing blunder or breach of proper etiquette, often made in front of other people. Daria didn't realize she had made such a faux pas when she went to use her salad fork to eat the main course. I really made a faux pas when I asked Julia about her surprise party—which hadn't happened yet. I made a serious faux pas on our first date by ordering veal, only realizing later that he's a staunch animal rights advocate.

(make/commit) a ˌfaux ˈpas

(from French) an action or a remark that causes embarrassment because it is not socially correct: I immediately made a faux pas when I forgot to take my shoes off before I went into the house. ♢ They were kind enough to overlook my faux pas and continued as if nothing had happened.

The meaning of the French expression is ‘wrong step’.