Gunslinger (or Gun Slinger)

The “gunslinger” (or “gun slinger”) is the legendary figure of the film western. The “gunslinger” term was not used in the 1800s, however; “gunman” (or “gun man”) is a term more of the period. It appears that the “gun slinger” term first appeared in western novels and silent film westerns, especially William Farnum’s western Drag Harlan in 1920.
   
   
Wikipedia: Gunslinger
Gunslinger, also gunfighter, is a name given to men in the American Old West who had gained a reputation as being dangerous with a gun.
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It was soon adopted by other western writers such as Zane Grey and became common usage. In his introduction to The Shootist author Glendon Swarthout says that gunslinger and gunfighter are modern terms and that the more authentic terms for the period would have been gunman, pistoleer, or shootist. While Swarthout seems to have been correct about gunslinger we know that Bat Masterson used the term gunfighter in the newspaper articles he wrote about the lawmen and outlaws he had known.
 
(Historical Dictionary of American Slang)
gunslinger a western gunfighter; gunman. Now Standard English.
1928 (cited in Webster’s 10th) 1931 Haycox Whispering Range 160: You’re one of Redmain’s imported gunslingers.
 
Old West Glossary
gunslinger A made-up word from Western fiction [1928]
   
(Oxford English Dictionary)
gun-slinger = GUN-MAN
1953 in Wentworth & Flexner Dict. Amer. Slang (1960) 236/1 The *gun-slinger will spend..his life behind bars.
 
Google Books
The Range Boss
By Charles Alden Seltzer
New York, NY: Grosset & Dunlap
1916
Pg. 226:
“He must have been a high-grade gun-slinger.”
 
Google Books
The Man of the Forest: A Novel
By Zane Grey
New York, NY: Grosset & Dunlap
1920
Pg. 363:
“Yep. Thet cowboy Las Vegas. An,’ boss, he turns out to be a gun-slinger from Texas.”
       
14 November 1920, Chicago Daily Tribune:
He was a “gun slinger,” bearing close relationship to the type of cowboy that existed in the old days of the far west, but who now is extinct save for pictorial perpetuation on the moving picture screens.
 
28 November 1920, Indianapolis Star, pg. 8, col. 4:
William Farnum will be the attraction at the Keystone this week in “Drag Harlan,” filmed from the story by Charles Alden Seltzer. Farnum is seen as “the two-gun man from Pardo,” a feared and notorious gunfighter. That his title as an outlaw is undeserved, but that his skill as a “gun slinger” is by no means overrated, is developed in the story.
   
25 January 1921, Wyoming State Tribune (Cheyenne, WY), pg. 2, col. 1:
LAST DAY FOR WILLIAM
FARNUM’S NEW PICTURE
 
Exciting pistol duels between famous “gun slingers” of the West is one of the big elements that holds the spectator’s interest in a vise-like grip while watching “Drag Harlan,” the latest of the William Farnum star series showing at the Atlas for the last times today. Farnum will play the part of “Drag,” the famous Pardo two-gun man, who rids an entire community of its outlaws. A charming romance runs parallel with the element of adventure.
   
23 March 1925, Olean (NY) Evening Herald, “The Hawk” by Dana Coolidge, pg. 2, col. 1:
“Git down, you pore fool. or he’ll beef you in your tracks. That’s one of them Texas gun slingers.”