A character in a professionally-produced video drama (no names, no blames) said deign, but the subtitles had dain. Realistically, I have to call that a mistake, but an online search found The Century Dictionary, which I was previously unaware of but which seems to be a major and authoritative (if slightly outdated) source. It records dain as an archaic spelling of deign, so maybe the subtitler was just being archaic rather than wrong, except the video drama is set in modern times, everyone speaks standard US English and the subtitles are otherwise 99.95% correct (there are a few slips, but no others worth commenting about). It also records dain as a shortened form of disdain, but it doesn’t give an example of either use.
I was surprised to find that deign and disdain share an etymology, despite the different spelling. Anglo-French de(s)deigner became Middle English disdainen, while Old French deignier became Middle English deinen, but at some point people reinserted the ‘g’ to reflect the Latin dignus (worthy) and dignārī (to judge worthy).
The tv comedy Mind your language ran from 1977 to 1979. I use it occasionally in class to illustrate vocabulary, grammar and communication. One episode (“Many happy returns”) is largely about money. It starts with Sid the college caretaker asking Gladys the tea lady for a free cup of tea, because he’s (something). She replies “You’re always skint, Sid!”. The subtitles (whether auto-generated or created by a human – some episodes are better than others) have “I’m a bit glacier mint”, but audibly that’s not what he says. I had always guessed that it is rhyming slang, as several other episodes show him using that, and even attempting to teach it to the students (one of whom refers to it as “cockeyed slanging rhyme”).
Fast-forward to a few days ago, when I was browsing through a book which I’ll donate or throw away soon. It has a section on Cockney rhyming slang, and one of the items is boracic lint. That is indeed what Sid says, but what is it? Wikipedia explains, quoting its entire article:
Boracic lint was a type of medical dressing made from surgical lint that was soaked in a hot, saturated solution of boracic acid and glycerine and then left to dry.
It has been in use since at least the 19th century, but is now less commonly used. When in use, boracic lint proved to be very valuable in the treatment of leg ulcers.
The term “boracic”, pronounced “brassic”, is also used as Cockney rhyming slang for having no money – “boracic lint” → “skint”.