A false step
Make no mistake about it; context clues help us understand words. (See Aug. 4 entry.)
In today’s Born Loser we can get a sense of what the French phrase faux pas means, because both men use a general synonym, mistake, in their dialogue. (Using a synonym is one way that a writer provides a context clue.)
More precisely, Webster’s says the word means, “a social blunder; error in etiquette; tactless act or remark.”
The phrase has been in our language since 1676, according to the online version of the Merriam-Webster Dictionary. It is pronounced “foe paw” and literally means false step.
When I worked in marketing communications, my firm had a major, somewhat hotheaded client who always pronounced the phrase “foo paw.” I gritted my teeth but said nothing. Correcting him, I feared, would be a false step in advancing my career.
Now, however, for the record, Mr. Ex-Client, wherever you are, it’s "FOE paw."