Green’s Dictionary of Slang

pertaining to confidence trickery or confidence tricksters; in a weak sense, deceitful.

1896		Ade Artie (1963) 83: I’d been readin’ them con story-books about pickin’ flowers and goin’ fishin’ and dubbin’ around the woods.
1906		C. M’Govern Sarjint Larry an’ Frinds 133: ‘Con’ stories wot soldiers pass along to each other just by way of killin’ time.
1919		Perrysburg Jrnl (Wood Co., OH) 22 May 2/1: It’s put this con life of our on the fritz, for fair!
1925		E. Jervis 25 Years in Six Prisons 56: My ‘con’ friends have said to me [...] ‘We soon get to know each other out there, and are ready for any game.’.
1936		J. Curtis Gilt Kid 20: Come on guy for a con gang, ain’t you?
1943		W.R. Burnett Nobody Lives for Ever 28: ‘Last thing of all he wants is to be buzzed by a broken-down con outfit’.
1953		F. Brown Madball (2019) 120: It would take slick con work, a really good song and dance.
1957		Kerouac letter 17 May in Charters II (1999) 35: W. C. Williams is sore about a big con letter Gregory wrote from Paris.
1962		R. Cook Crust on its Uppers 51: I wasn’t quite certain whether the whole thing was a giant con trick.
1997		L. Pettiway Workin’ It 109: I knew the basics of this con thing.