The thread on wonk reminded me of this word, meaning dodgy, crooked. OED terms it Australian slang and has a first cite of 1970. In fact all its cites are Australian, but this has been around in the UK equally as long. It was certainly common here in the 70s, and possibly the 60s, although memory is notoriously deceptive.
OED relates it speculatively to an earlier shonk, shonky, a disparaging Cockney term for Jews (a shortening of schonicker, origin uncertain). I’ve never heard that sense, but I did always associate the later sense with London slang. I’ll try to dig up some early British cites for that sense.
Any other Brits on the board remember it from the 60s/70s?