The Quick & The Dead. This phrase has been around forever, I mean it is in the Bible:
Wikipedia has an enlightening blurb. Essentially "quick" meant living, and so we get the line in the Apostle's Creed:
The application to gunfighting comes from a book by Louis L'Amour (or maybe an even earlier book by Ellery Queen), which was made into a movie in 1987 with Sam Elliot, and later remade with Sharon Stone, purtiest gunfighter this side of the Mississippi. What's the deal with Sharon Stone anyway? A few (several? many?) years ago she was queen of Hollywood, then she kind of fell off the map.