Unriddle means to solve a mystery or a puzzle. Some antonyms for the word "un-riddle" could be puzzle, mystify, confound, baffle, or bewilder. These words describe the act of making something unclear or difficult to understand. Other antonyms for "un-riddle" could be hide, obscure, mask, veil, or shroud. These words describe the act of concealing or obscuring something so that it cannot be easily understood or discovered. Overall, there are many different antonyms for the word "un-riddle," each of which conveys a slightly different meaning and nuance to the concept of solving mysteries or puzzles.