Green’s Dictionary of Slang

(US black) illegally distilled alcohol.

1927		AS III:1 25: The liquor on tap at these dances is called ‘pinetop,’ ‘Shinny,’ ‘white mule,’ or ‘corn.
c.1947		Eliason Words Lists (Florida) 11: Shinny [...] bad corn liquor made from cane-skinnings.
1966–67		in DARE questionnaire.