The Collaborative International Dictionary of English v.0.48:

Spongy \Spon"gy\ (sp[u^]n"j[y^]), a.
   1. Soft, and full of cavities; of an open, loose, pliable
      texture; as, a spongy excrescence; spongy earth; spongy
      cake; spongy bones.
      [1913 Webster]

   2. Wet; drenched; soaked and soft, like sponge; rainy.
      "Spongy April." --Shak.
      [1913 Webster]

   3. Having the quality of imbibing fluids, like a sponge.
      [1913 Webster]

   Spongy lead (Chem.), sponge lead. See under Sponge.

   Spongy platinum. See under Platinum.
      [1913 Webster]