Q From Kelli Allison: A British friend tells me that the term hillbillies refers to the Irish who fled from William III to the USA and took up residence in the hills of Tennessee etc. It sounds feasible, but is my friend correct?
A It sounds a most unlikely theory, and the linguistic evidence is certainly against it. The word billy (of which hillbilly is a compound) is an English word that goes back to the early sixteenth century at least, at first meaning a friend or comrade, and later any male person, a rough equivalent of “fellow”. Hillbilly, in the sense of a rustic person, is first attested only at the very end of the nineteenth century; if it were connected with Good King Billy, it ought to have appeared much earlier.