Sprezzatura (Italian pronunciation: [sprettsaˈtura]) is an Italian word originating from Baldassare Castiglione's The Book of the Courtier, where it is defined by the author as "a certain nonchalance, so as to conceal all art and make whatever one does or says appear to be without effort and almost without any thought about it". It is the ability of the courtier to display "an easy facility in accomplishing difficult actions which hides the conscious effort that went into them". Sprezzatura has also been described "as a form of defensive irony: the ability to disguise what one really desires, feels, thinks, and means or intends behind a mask of apparent reticence and nonchalance".
The word has entered the English language; the Oxford English Dictionary defines it as "studied carelessness".
(cited from Wikipedia)