The Collaborative International Dictionary of English v.0.48:

Downy \Down"y\ (-[y^]), a.
   1. Covered with down, or with pubescence or soft hairs. "A
      downy feather." --Shak.
      [1913 Webster]

            Plants that . . . have downy or velvet rind upon
            their leaves.                         --Bacon.
      [1913 Webster]

   2. Made of, or resembling, down. Hence, figuratively: Soft;
      placid; soothing; quiet. "A downy shower." --Keble. "Downy
      pillow." --Pope.
      [1913 Webster]

            Time steals on with downy feet.       --Young.
      [1913 Webster]

   3. Cunning; wary. [Slang, Eng.] --Latham.
      [1913 Webster]

WordNet (r) 3.0 (2006):

downy
    adj 1: like down or as soft as down [syn: downy, downlike,
           flossy, fluffy]
    2: covered with fine soft hairs or down; "downy milkweed seeds"
       [syn: downy, pubescent, puberulent, sericeous]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "downy":
   airy, artful, astute, attenuate, attenuated, bubbly, crafty,
   cunning, dainty, deep, delicate, ethereal, even, feathery, filmy,
   fine, fine-drawn, fine-grained, finespun, flat, fleecy, flossy,
   fluffy, foamy, frothy, furry, fuzzy, gauzy, glabrate, glabrescent,
   glabrous, gossamer, gossamery, guileful, hirsute, imponderous,
   insidious, lanate, leger, leiotrichous, level, light, light as air,
   lighter than vanity, mousse, nappy, peachy, pinnate, plane,
   pubescent, refined, regular, satin, satiny, silky, sly, smooth,
   smooth-shaven, smooth-textured, souffle, suave, thin-spun, tricky,
   unbroken, unheavy, uniform, unrough, unroughened, unruffled,
   velutinous, velvety, volatile, weightless, wily, wiredrawn, woolly,
   yeasty