Green’s Dictionary of Slang

heel-grifter n.

[heel n. (2) + grifter n. (1)]

(US Und.) a small-time or second-rate con-man.

[US]D. Maurer Big Con 142: Some heel-grifters think it is [...] sophisticated to appear languid.
[US]J. Ridley Love Is a Racket 33: Wesker. Just another con, just another heel grifter.