Source : Webster's Revised Unabridged Dictionary (1913)

Adust \A*dust"\, a. [L. adustus, p. p. of adurere: cf. F.
   aduste.]
   1. Inflamed or scorched; fiery. ``The Libyan air adust.''
      --Milton.

   2. Looking as if or scorched; sunburnt.

            A tall, thin man, of an adust complexion. --Sir W.
                                                  Scott.

   3. (Med.) Having much heat in the constitution and little
      serum in the blood. [Obs.] Hence: Atrabilious; sallow;
      gloomy.

Source : WordNet®

adust
     adj 1: dried out by heat or excessive exposure to sunlight; "a vast
            desert all adust"; "land lying baked in the heat";
            "parched soil"; "the earth was scorched and bare";
            "sunbaked salt flats" [syn: {baked}, {parched}, {scorched},
             {sunbaked}]
     2: burned brown by the sun; "of an adust complexion"- Sir
        Walter Scott