Back in the 1960s we had a President, Lyndon B. Johnson from Texas, with a heavy Texas accent. When he'd do a tv address, It'd start with, "My fellow merkins." It became a standard joke that we were "merkins". So, back on topic, from here on this side of the pond, some of the terms we 'merkins' use are, 'dumb-ass', or 'shit-for-brains', or 'f....ing moron', or 'dipshit'. (The etiology of or meaning of that last one, I have no idea.) A good one, rarely used nowadays, was 'can't tell shit from shoe polish'
I've modified that one, for use in mixed company, into, "in deep tapioca now". One can't always speak freely.
Dipshit means someone who is easily fooled. The person doing the fooling is said to have dipped them in shit, ergo they are a dipshit. Nothing at all to do with deep shit. I love the use of merkin especially given it’s true meaning
I'm not sure your definition is correct matey, to me a knackers yard was the area outside an abbatoir where the blood, and offal were disposed of.
"...the area outside an abbatoir..." Vlad, that word took be back in time. I grew up in south Louisiana in the '50s when French words were still heard in conversation (unlike today). There was one a few blocks from our house. My father spoke both English and 'cajun French', but lost it over time, and I never learned any until university.
There was an abbatoir for the locals on a desolate stretch of road where I grew up. Nobody liked being nearby...