If you want a Scotch name why don't you call him Jock? Macgregor looked disgusted. Because Jock is not a name, but a diminutive, as everybody knows well. It is the diminutive of John. And John is not a Scots name. The Scots form of that name is Ian. If you want to call him Ian Fetch, I shall say no more.
usage note: Usually the noun is part of a noun phrase explicitly denoting the particular speciality, such as a compiler jock or a systems jock. Usage of the word alone with this meaning is rare.