Southern African informal a variant of sis 2
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Examples from the Web for sies
Historical Examples of sies
Evening, o̍hksies (o full; sies distinctly pronounced; e ½).
But, at the point of the whip, Sies grandfather drove them all back inland to a hut where they could take refuge.The Story of My Life, volumes 4-6
Augustus J. C. Hare