Green’s Dictionary of Slang

shifter n.1

[SE shift, to employ underhand methods, to deceive, also to live by one’s wits; note the nickname of the resourceful but impoverished Sporting Times journalist William Farn Goldberg, ‘The Shifter’]

1. [mid-16C–17C; 1920s] (UK Und.) a trickster, a confidence man.

2. [early 19C] (UK Und.) a warning from one thief to another.

3. [1920s+] (US Und.) a receiver of stolen goods.