Green’s Dictionary of Slang

(US) countrified, rural, unsophisticated.

1942		Berrey & Van den Bark Amer. Thes. Sl.
1960		G. Swarthout Where the Boys Are 105: ‘May be hicky,’ I confessed, ‘coming from a small town’n stuff but I’m not really.’.
1970		D. Jenkins Saturday’s America 258: ‘Arkansas is a hicky place. All they do is sell jelly and cider by the side of the road’.
1981		M. Baker Nam (1982) 12: I’m from Bakersfield. It’s pretty hicky, but a lot of America is pretty hicky.
2001		G. Coughlan Everyday Eng. and Sl. 🌐 Hick or Hickey/Hickster (a/n): unfashionable.