The Collaborative International Dictionary of English v.0.48:

dusty \dust"y\ (d[u^]st"[y^]), a. [Compar. Dustier
   (d[u^]st"[i^]*[~e]r); superl. Dustiest
   (d[u^]st"[i^]*[e^]st).] [AS. dystig. See Dust.]
   1. Filled, covered, or sprinkled with dust; clouded with
      dust; as, a dusty table; a dusty attic; also, reducing to
      dust.
      [1913 Webster]

            And all our yesterdays have lighted fools
            The way to dusty death.               --Shak.
      [1913 Webster]

   2. Like dust; of the color of dust; as, a dusty white.
      [1913 Webster]

   Dusty miller (Bot.), a plant (Cineraria maritima); -- so
      called because of the ashy-white coating of its leaves.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dusty
    adj 1: covered with a layer of dust; "a dusty pile of books"
           [syn: dusty, dust-covered]
    2: lacking originality or spontaneity; no longer new; "moth-
       eaten theories about race"; "stale news" [syn: cold,
       stale, dusty, moth-eaten]

Moby Thesaurus II by Grady Ward, 1.0:

216 Moby Thesaurus words for "dusty":
   Quaker-colored, Saharan, acier, anhydrous, arid, ashen, ashy,
   athirst, barren, blah, blank, bloodless, bone-dry, branny,
   broken-record, bromidic, canescent, chalklike, chalky,
   characterless, cinereous, colorless, comminute, comminuted,
   crumbling, crushed, dapple, dapple-gray, dappled, dappled-gray,
   dead, desert, detrital, detrited, dilapidated, dingy, dirty,
   disintegrated, dismal, dove-colored, dove-gray, draggy, drearisome,
   dreary, droughty, dry, dry as dust, dryasdust, dull, effete,
   efflorescent, elephantine, empty, etiolated, everlasting, fade,
   farinaceous, fine, flaky, flat, floury, furfuraceous, fusty,
   glaucescent, glaucous, gone to dust, gone to seed, grated, gray,
   gray-black, gray-brown, gray-colored, gray-drab, gray-green,
   gray-spotted, gray-toned, gray-white, grayed, grayish, grimy,
   griseous, grizzle, grizzled, grizzly, ground, grubby, grungy,
   harping, heavy, high and dry, ho-hum, hollow, humdrum, impalpable,
   inane, inexcitable, insipid, invariable, iron-gray, jejune,
   jog-trot, juiceless, lead-gray, leaden, levigated, lifeless,
   like parchment, livid, long-winded, low-spirited, mealy, messy,
   mildewed, milled, miry, moldering, moldy, monotonous, moss-grown,
   moth-eaten, mouse-colored, mouse-gray, mousy, muddy, musty, pale,
   pallid, pearl, pearl-gray, pearly, pedestrian, pestled, plodding,
   pointless, poky, ponderous, powdered, powdery, prolix, pulverant,
   pulverized, pulverulent, reduced to powder, road-weary, ruined,
   ruinous, rusty, sad, sandy, sapless, scaly, scobicular, scobiform,
   scruffy, scurfy, sharded, shredded, silver, silver-gray, silvered,
   silvery, singsong, slate-colored, slaty, slovenly, slow, smirchy,
   smoke-gray, smoky, smudgy, smutchy, smutty, snuffy, sober, solemn,
   somber, sooty, spiritless, stale, steel-gray, steely, sterile,
   stiff, stodgy, stone-colored, stuffy, superficial, tasteless,
   taupe, tedious, thirsting, thirsty, time-scarred, timeworn,
   travel-jaded, travel-sated, travel-stained, travel-weary,
   travel-worn, treadmill, triturated, undamped, uneventful,
   uninteresting, unlively, untidy, unvarying, unwatered, vapid,
   waterless, way-weary, wayworn, weariful, wearisome, wooden, worn