The Collaborative International Dictionary of English v.0.48:

Dewy \Dew"y\, a.
   1. Pertaining to dew; resembling, consisting of, or moist
      with, dew.
      [1913 Webster]

            A dewy mist
            Went and watered all the ground.      --Milton.
      [1913 Webster]

            When dewy eve her curtain draws.      --Keble.
      [1913 Webster]

   2. Falling gently and beneficently, like the dew.
      [1913 Webster]

            Dewy sleep ambrosial.                 --Cowper.
      [1913 Webster]

   3. (Bot.) Resembling a dew-covered surface; appearing as if
      covered with dew.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dewy
    adj 1: wet with dew [syn: bedewed, dewy]

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "dewy":
   boggy, budding, callow, damp, dampish, dank, ever-new, evergreen,
   fenny, firsthand, fledgling, fresh, green, growing, humid,
   immature, impubic, inexperienced, ingenuous, innocent, intact,
   juicy, maiden, maidenly, marshy, minor, moist, muggy, naive,
   neoteric, nestling, new, new-fledged, original, pristine, rainy,
   raw, ripening, roric, roriferous, sappy, sempervirent, sticky,
   swampy, tacky, tender, unadult, unbeaten, underage, undeveloped,
   undried, unfledged, unformed, unhandled, unlicked, unmellowed,
   unripe, unseasoned, untouched, untried, untrodden, unused, vernal,
   virgin, virginal, wet, wettish, young