isiphawulimore incredible, most incredible
1ngokungekho sikweni-mangalisa(yo)He ran an incredible distance — Wabaleka umgama omangalisayo→ Synonym of amazing
2(impossible to believe)-ngakholelekiyoHis story's incredible. He's lying — Ibali lakhe alikholeleki. Uyaxoka
The first meaning is informal, and you should not use this in serious writing.