"confidence trickster," 1906, carnival and circus slang, probably an alteration of grafter (see graft (n.2); also compare grift). Gradually extended to "any non-violent criminal."
Entries linking to grifter
graft n.2
"corruption," 1865, perhaps 1859, American English, perhaps from British slang graft "one's occupation" (1853), which is perhaps from the identical word meaning "a ditch, moat," literally "a digging" (1640s), from Middle Dutch graft, from graven "to dig" (see grave (v.)).
grift
1906 (n.); 1915 (v.), U.S. underworld slang, perhaps a corruption of graft (n.2).