Literally - Know how to do
Usually used, as most French terms - je ne sais pas
, to describe that certain something that is beyond normal language.
Nowdays it is often referred to (incorrectly) as X-factor
However Savior faire suggests a certain style, accomplishment and refinement. A person who has Savoir faire is naturally suave and classy, or has the innate abiilty to do or say the right thing at the right time.
The great Irish wit, Oscar Wilde
, has considered to have Savoir faire, although he probably would have said that he was more Laisser faire (i.e. lazy, disinterested or libertine)
or in a more modern context;
The actor George Clooney
can be said to have Savoir faire