A manservant can become an accounts man, a hillbilly a blue-blooded Manhattan prince.
The takeaway from Buckwild could be the strong bond of youthful friendship—a hillbilly version of us against the world.
In rural Appalachia, the drug is sometimes referred to as “hillbilly heroin.”
"southern Appalachian U.S. resident," by 1892, from hill + masc. proper name Billy/Billie.
Then again, I do not think It will do so well. I would hate to see some old railroad man come here and take my job, and then, I don t think It is right to hire some Hill Billy and give him the same right as I just because he was hired the same time I was. ["The Railroad Trainmen's Journal," vol. IX, July 1892]In reference to a type of folk music, first attested 1924.
In short, a Hill-Billie is a free and untrammelled white citizen of Alabama, who lives in the hills, has no means to speak of, dresses as he can, talks as he pleases, drinks whiskey when he gets it, and fires of his revolver as the fancy takes him. ["New York Journal," April 23, 1900]