moldy

1. Covered with or containing mold: moldy bread.
2. Musty or stale, as from age or decay.

adjective

Smelling of mildew or decay: frowzy, fusty, musty, putrid, rancid, rank², rotten. See smells/good smells/bad smells/smell.

Animal feed overgrown with fungus; the feed may be harvested and stored or be still in the ground.

• m. corn disease — see leukoencephalomalacia, fusarium moniliforme.
• m. feed — causes mycotoxic nephropathy in horses.
• m. garden beans — causes acute interstitial pneumonia in cattle.
• m. hay — see micropolyspora faeni.
• m. sweet clover — melilotus alba.
• m. sweet potato — fusarium javanicum.

The adjective has one meaning:

Meaning #1: covered with or smelling of mold
  Synonyms: mouldy, musty