Green’s Dictionary of Slang

(US) a derog. name for a black person.

1941		Warner, Junker & al. Color & Human Nature 243: This woman and others like her stress the value of their appearance in securing white patrons. One who for some years has been mistress to a white man (‘I couldn’t be bothered with those cheap zigs’).
1944		Mencken ‘Designations for Colored Folk’ in AS XIX:3 174: The DAE does not list such vulgar synonyms for Negro as [...] jigabo (with the variants, jibagoo, jig, zigabo, zigaboo, zig).
1947		S. Lewis Kingsblood Royal (2001) 16: I thought all zigs were wonderful at sweet potatoes.
1962		P. Crump Burn, Killer, Burn! 109: Got any weapons, zig?