Green’s Dictionary of Slang

shit-heel n.

also shithealer, shit-heeler

1. (US) a generally derog. term of abuse; a contemptible person.

[US]J. Steinbeck Grapes of Wrath (1951) 142: Truck drivers. That’s the stuff [...] Hope they stop; take away the taste of them shit-heels.
[US] in G. Legman Limerick (1953) 248: There was a young man of Porcellian, / A rotter, a shit-heel, a hellion.
[US]Goldin et al. DAUL 192/1: Shit-heel (Variant, Shit-heeler). A contemptible person.
[US](con. 1940s) G. Mandel Wax Boom 49: You brown-nosing shit-healer.
[US]‘Iceberg Slim’ Mama Black Widow 23: He’s still bouncing the shit-heels outta’ the joint.
[US]San Diego Sailor 76: It made me feel like a shit-heel.
[US]Big Audio Dynamite ‘Sambadrome’ [lyrics] You dirty little shitheel.
[US](con. early 1950s) J. Ellroy L.A. Confidential 44: A younger guy who treated them nice and gave them a taste all men weren’t shitheels.
[Can](con. 1920s) O.D. Brooks Legs 113: I put a little air between the big shitheel and myself.
[US](con. 1964–8) J. Ellroy Cold Six Thousand 516: Goyishe shitheels. Mormons are roughly synonymous with the Ku Klux Klan.
[Aus]J.J. DeCeglie Drawing Dead [ebook] Did you find my daughter [...] I bet you didn’t you...you fucking shitheel.

2. (UK/US Und.) an informer.

[US]Bentley & Corbett Prison Sl. 36: Snitchalso Rat An informant. […] (Archaic: crimp, shit-heel, buzz man, belcher).