Source : Webster's Revised Unabridged Dictionary (1913)

Viewless \View"less\, a.
   Not perceivable by the eye; invisible; unseen. ``Viewless
   winds.'' --Shak.

         Swift through the valves the visionary fair Repassed,
         and viewless mixed with common air.      --Pope.

Source : WordNet®

viewless
     adj : not having or expressing opinions or views