The Collaborative International Dictionary of English v.0.48:

Exasperation \Ex*as`per*a"tion\, n. [L. exasperatio: cf. F.
   exasp['e]ration.]
   1. The act of exasperating or the state of being exasperated;
      irritation; keen or bitter anger.
      [1913 Webster]

            Extorted from him by the exasperation of his
            spirits.                              --South.
      [1913 Webster]

   2. Increase of violence or malignity; aggravation;
      exacerbation. "Exasperation of the fits." --Sir H. Wotton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

exasperation
    n 1: an exasperated feeling of annoyance [syn: aggravation,
         exasperation]
    2: actions that cause great irritation (or even anger)