Source : Webster's Revised Unabridged Dictionary (1913)

Unriddle \Un*rid"dle\, v. t. & i. [1st pref. un- + riddle.]
   To read the riddle of; to solve or explain; as, to unriddle
   an enigma or a mystery. --Macaulay.

         And where you can't unriddle, learn to trust.
                                                  --Parnell.