Source : Webster's Revised Unabridged Dictionary (1913)

Undreamed \Un*dreamed"\, Undreamt \Un*dreamt"\, a.
   Not dreamed, or dreamed of; not th?ught of; not imagined; --
   often followed by of.

         Unpathed waters, undreamed shores.       --Shak.

Source : WordNet®

undreamt
     adj : not imagined even in a dream [syn: {undreamed}, {undreamed
           of}, {undreamt of}, {unimagined}]