Green’s Dictionary of Slang

1. a confidence trickster.

1929

C.G. Givens ‘Chatter of Guns’ in Sat. Eve. Post 13 Apr.; list extracted in AS VI:2 (1930) 134: salesman, n. Confidence man.

2. a pimp.

1949		Monteleone Criminal Sl. (rev. edn).
1968		‘Sl. of Watts’ in Current Sl. III:2.