The Diary—Old Hoax or New?

[Sam Flynn]

That would apply Sam,if the transition was derived from an industrial term

It did. Even if it didn't, there's no evidence that it existed before well into the 20th century, and there's plenty of evidence to show that it only became widely used in the latter part of it.

[harry]

That would apply Sam,if the transition was derived from an industrial term.There is no indication that it did.It could have,but like a great deal of the English language,origins are sometimes hard to tie down. Even if it can't be shown to have mutated before the twentieth century,c an evidence prove it didn't.
T ake the expression,'good morning alltogether'.I have only ever heard one person use it.Does that mean no one else ever has?

[Sam Flynn]

Exacly Sam,but my point is, the more 'one off's' there are,the more likely it is of someone noticing it,and becoming aware of the possibilities of creating an abstract entity or action with it.

It's not just a case of stitching words together on a whim - "one off [object]" has first to transition from being a specialist manufacturing industrial term into non-specialist everyday usage, which would take time in itself. After that, it then needs to mutate from "one off [object]" to "one-off [abstract thing]". There is no evidence that the latter occurred before the 20th century, and it's hard to see why or how it should have. However, during the 20th century - particularly towards its end - just about everybody was using the term in that way.

[Iconoclast]

Exacly Sam,but my point is, the more 'one off's' there are,the more likely it is of someone noticing it,and becoming aware of the possibilities of creating an abstract entity or action with it. Why couldn't this have happened in the late 1800's? Not an impossible scenario ,is it?

If it wasn't for the implications in terms of the mooted hoaxed diary of Jack the Ripper, I very much doubt many people would argue overly vehemently with you on this point. If the debate was going on for a high school English lesson, I suspect more people would take the position you take and accept that the routine conjunction of 'one' and 'off' may reasonably have led to expressions along the lines of 'one off event' evolving naturally. If we had every document and every letter ever written in the late Victorian period and convenient recordings of every conversation during this time (oh for an historical Alexa), we might well find that 'one off moment' was not so psychologically (or linguistically) unbridgeable after all.

Ike

[harry]

I am quite aware there were also a largge number of misspellings.I do not include those.