Source : Webster's Revised Unabridged Dictionary (1913)

Dusty \Dust"y\, a. [Compar. {Dustier}; superl. {Dustiest}.] [AS.
   dystig. See {Dust}.]
   1. Filled, covered, or sprinkled with dust; clouded with
      dust; as, a dusty table; also, reducing to dust.

            And all our yesterdays have lighted fools The way to
            dusty death.                          --Shak.

   2. Like dust; of the color of dust; as a dusty white.

   {Dusty miller} (Bot.), a plant ({Cineraria maritima}); -- so
      called because of the ashy-white coating of its leaves.

Source : WordNet®

dusty
     adj : covered with a layer of dusty; "a dusty pile of books" [syn:
            {dust-covered}]
     [also: {dustiest}, {dustier}]

dustier
     See {dusty}