folkie (n.)youdaoicibaDictYouDict[folkie 词源字典]
"devotee of (modern) folk music," attested by 1966; with -ie.[folkie etymology, folkie origin, 英语词源]
hillbilly (n.)youdaoicibaDictYouDict
"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 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]
In reference to a type of folk music, first attested 1924.
hootenanny (n.)youdaoicibaDictYouDict
"informal session of folk musicians," 1940, American English, earlier "a gadget" (1927), of unknown origin, perhaps a nonsense word.
Another device used by the professional car thief, and one recently developed to perfection, according to a large Chicago lock-testing laboratory, is a "hootenanny," so-called by the criminals using it. ["Popular Mechanics," February 1931]