Source : Webster's Revised Unabridged Dictionary (1913)

Exasperate \Ex*as"per*ate\, v. t. [imp. & p. p. {Exsasperated};
   p. pr. & vb. n. {Exasperating}.]
   1. To irritate in a high degree; to provoke; to enrage; to
      exscite or to inflame the anger of; as, to exasperate a
      person or his feelings.

            To exsasperate them against the king of France.
                                                  --Addison.

   2. To make grievous, or more grievous or malignant; to
      aggravate; to imbitter; as, to exasperate enmity.

            To exasperate the ways of death.      --Sir T.
                                                  Browne.

   Syn: To irritate; provoke. See {Irritate}.

Source : WordNet®

exasperating
     adj 1: extremely annoying or displeasing; "his cavelier curtness of
            manner was exasperating"; "I've had an exasperating
            day"; "her infuriating indifference"; "the ceaseless
            tumult of the jukebox was maddening" [syn: {infuriating},
             {maddening}, {vexing}]
     2: making worse [syn: {aggravating}, {exacerbating}]