It seems to come from a 13c Middle English interjection ho or hoo (an exclamation meaning "halt!" or a call to get attention), which may itself come from the earlier Old Norse, hó!
The modern day word “whoa”, meaning stop, is from the same root.
That was fun, thanks to Chalicea.
Brendan, I use the printed book too but that facility must speed things up. Life surely gets harder for setters with all the work-arounds nowadays, anagram solvers etc which I use regularly.
I agree with teenieleek about the increasingly difficult task for setters these days. Although I do use anagram solvers and word wizard, I do check potential solutions in a dictionary as well.
I too enjoyed this one.
wrt solving clues I find the BRB invaluable in ensuring that both the definition and parsing are correct - although I can, and do, get things wrong, as I had in Listener 4939.
I suppose someone has to mention the actual puzzle…. A quick solve as I was pretty certain what the two sets of last words were and early confirmation came from the crossing perimeter and extra letters. I believe that historians regard both sets as confected, the first soon after the death and the second a long time later.