The Grauniad's Hadley Freeman refers to Michael Cohen, of the alleged wire-fraud and the checked jacket, as nothing more than a shonky used-car salesman in a column today. I had come across the word shonky a few times and inferred its meaning—unreliable, untrustworthy, shoddy. I hadn't thought about its derivation, though, and I thought that perhaps y'all might be interested, so: to the OED, W&S friends!
And, well, they don't really know. Ah, well.
But—and this is a big but—it just might be related to the noun shonk or shonniker, which was an ethnic slur term for Jews. It might not be! It's hard to be sure. The slur was in use in England in the mid-20th century and may have transferred to Australia after, possibly (but probably not) losing its anti-Semitic specificity. A Google search seems to indicate that shonk and spiv are definitely connected in Australia, at least rhetorically. I don't know that anyone thinks of either of them as anti-Semitic, but then I have heard that Australians use the slang motza (or motzer) to mean a large sum of money without anyone thinking of it as anti-Semitic, either. You know?
Anyway, I am not actually offended. It seems unlikely that Hadley Freeman (who is Jewish and occasionally writes about anti-Semitism) used a term with anti-Semitic connotations to describe an attorney named Cohen. It is more likely that the term, whatever its derivation, does not actually have those anti-Semitic overtones. And yet, to be honest, having looked it up, I don't think I would be comfortable using it myself, either.