The Collaborative International Dictionary of English v.0.48:

Tristful \Trist"ful\ (tr[i^]st"f[.u]l), a.
   Sad; sorrowful; gloomy. --Shak.
   [1913 Webster]

         Eyes so tristful, eyes so tristful,
         Heart so full of care and cumber.        --Longfellow.
   [1913 Webster]