The Collaborative International Dictionary of English v.0.48:

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
      excite or to inflame the anger of; as, to exasperate a
      person or his feelings.
      [1913 Webster]

            To exsasperate them against the king of France.
                                                  --Addison.
      [1913 Webster]

   2. To make grievous, or more grievous or malignant; to
      aggravate; to imbitter; as, to exasperate enmity.
      [1913 Webster]

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

   Syn: To irritate; provoke. See Irritate.
        [1913 Webster]