The Collaborative International Dictionary of English v.0.48:

Mildew \Mil"dew\, v. t. [imp. & p. p. Mildewed; p. pr. & vb.
   n. Mildewing.]
   To taint with mildew; as, mildewed clothing.
   [1913 Webster]

         He . . . mildews the white wheat.        --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mildew \Mil"dew\, v. i.
   To become tainted with mildew.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mildew \Mil"dew\, n. [AS. melede['a]w; akin to OHG. militou, G.
   mehlthau, mehltau; prob. orig. meaning, honeydew; cf. Goth.
   milip honey. See Mellifluous, and Dew.] (Bot.)
   A growth of minute powdery or webby fungi, whitish or of
   different colors, found on various diseased or decaying
   substances.
   [1913 Webster]

   powdery mildew a fungal disease of plants caused by an
      ascomycete of the order Erysiphales, characterized by a
      powdery white film on the surface of the affected plants.
      It is damaging to, e.g., roses and lilacs. Also, a fungus
      that causes such a disease.
      [PJC]

WordNet (r) 3.0 (2006):

mildew
    n 1: the process of becoming mildewed [syn: mildew, mold,
         mould]
    2: a fungus that produces a superficial (usually white) growth
       on organic matter
    v 1: become moldy; spoil due to humidity; "The furniture molded
         in the old house" [syn: mold, mildew]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "mildew":
   biodegradability, biodegradation, blast, blight, break up, breakup,
   cancer, canker, corrosion, corrupt, corruption, crumble,
   crumble into dust, decay, decompose, decomposition, degradability,
   degradation, dilapidation, disintegrate, disintegration,
   disorganization, dissolution, dry rot, fall into decay,
   fall to pieces, fester, fetidity, fetidness, foulness, frowst,
   frowstiness, frowziness, fungus, funkiness, fustiness, gangrene,
   go bad, go to pieces, malodorousness, mold, molder, moldiness,
   mortify, moth, moth and rust, must, mustiness, necrose,
   noisomeness, odorousness, offensiveness, oxidation, oxidization,
   pest, putrefy, putresce, putridness, rancidity, rancidness, rankle,
   rankness, reastiness, repulsiveness, resolution, rot, rottenness,
   rust, smelliness, smut, sphacelate, spoil, spoilage, stinkingness,
   stuffiness, suppurate, worm



Easton's 1897 Bible Dictionary:

Mildew
   (the rendering of a Hebrew word meaning "to be yellow,"
   yellowness), the result of cutting east winds blighting and thus
   rendering the grain unproductive (Deut. 28:22; 1 Kings 8:37; 2
   Chr. 6:28).