Savoir faire is French for to know how to do. In English, we use it as a noun referring to the ability to do the right or appropriate thing in any situation. A person with savoir faire has admirable confidence and poise in social situations of all kinds. There is no exact English equivalent to savoir faire, which is why it survives in the language, but social grace, diplomacy, and tact come close.
The term is sometimes hyphenated and sometimes not. There is no universal standard for this, and the hyphenated and unhyphenated forms appear about equally often throughout the English-speaking world. The phrase is well established in English—it has been in the language about two centuries—so there is no need to italicize it in normal use.
In short, this is James Bond with all the savoir-faire of a molester in a mosh pit. [Palm Beach Post]
Unlike the essentially German Windsors, the essentially French Grimaldis displayed savoir-faire in their dealings with those of us who pressed our noses against their windows. [The Observer]
He is in no hurry, and his sense of pleasure is partly in other people’s terrified scrambling and partly in his own flick-of-the-wrist savoir-faire. [New York Times]
She even suggested that Withers consider finishing school to polish up her savoir faire. [ABC News]
Obama has dazzled the media with his easy manner and his savoir faire, but he’s not the right man for the job. [CounterPunch]