The Collaborative International Dictionary of English v.0.48:

Massy \Mass"y\, a. [Compar. Massier; superl. Massiest.]
   Compacted into, or consisting of, a mass; having bulk and
   weight or substance; ponderous; bulky and heavy; weighty;
   heavy; as, a massy shield; a massy rock.
   [1913 Webster]

         Your swords are now too massy for your strengths,
         And will not be uplifted.                --Shak.
   [1913 Webster]

         Yawning rocks in massy fragments fly.    --Pope.
   [1913 Webster]