Literally - Know how to do

Usually used, as most French terms - je ne sais pas, ennui, 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
by TJ Curtis September 28, 2006
When you know just what do do, related to a subject.
He knew right where to do, liek he had done it a thousand times. What savoir-faire.
by Larstait November 16, 2003
Street know-how; street smarts. As popularized by the Disney movie "Oliver and Company."
Why should I worry?
Why should I care?
I may not have a dime
But I got street savoir faire
by JohnNameJohn February 10, 2011
The personal adjective for when one gives no fucks because in the end, even if they have no possessions or money to their name, they have street smarts that will let them not only survive on the street with nothing, but thrive.
"Why should i worry? why should I care? I may not have a dime, but i got street savoir-faire!" - Pongo, Oliver and Company
by Elvi Elthree March 28, 2013