Boak is a word which rhymes with poke and was used a few times in the Kate Atkinson book Not the End of the World, which I reviewed yesterday.
It is a verb meaning to be sick, as in vomit. So it isn’t very pleasant but is used often, for instance:-
I drank so much Irn Bru (insert your own choice of poison) that I boaked.
He scunnered me that much, I boaked all over him.
Wid that no’ gie you the dry boak.
The last phrase is generally used to signify that something absolutely disgusts you.
The dry boak is what happens when you just retch and nothing comes up because your stomach has been emptied.
So, boak is a useful but not exactly charming word.
I hope I haven’t given you the boak at the thought of it, or even the dry boak.