The Collaborative International Dictionary of English v.0.48:

Moldy \Mold"y\, Mouldy \Mould"y\, a. [Compar. Moldieror
   Mouldier; superl. Moldiest or Mouldiest.] [From Mold
   the growth of fungi.]
   Overgrown with, or containing, mold; smelling of mold; as,
   moldy cheese or bread.
   [1913 Webster]