The Collaborative International Dictionary of English v.0.48:

Aggravate \Ag"gra*vate\, v. t. [imp. & p. p. Aggravated; p.
   pr. & vb. n. Aggravating.] [L. aggravatus, p. p. of
   aggravare. See Aggrieve.]
   1. To make heavy or heavier; to add to; to increase. [Obs.]
      "To aggravate thy store." --Shak.
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   2. To make worse, or more severe; to render less tolerable or
      less excusable; to make more offensive; to enhance; to
      intensify. "To aggravate my woes." --Pope.
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            To aggravate the horrors of the scene. --Prescott.
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            The defense made by the prisoner's counsel did
            rather aggravate than extenuate his crime.
                                                  --Addison.
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   3. To give coloring to in description; to exaggerate; as, to
      aggravate circumstances. --Paley.
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   4. To exasperate; to provoke; to irritate. [Colloq.]
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            If both were to aggravate her parents, as my brother
            and sister do mine.                   --Richardson
                                                  (Clarissa).
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   Syn: To heighten; intensify; increase; magnify; exaggerate;
        provoke; irritate; exasperate.
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The Collaborative International Dictionary of English v.0.48:

Aggravating \Ag"gra*va`ting\, a.
   1. Making worse or more heinous; as, aggravating
      circumstances.
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   2. Exasperating; provoking; irritating. [Colloq.]
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            A thing at once ridiculous and aggravating. --J.
                                                  Ingelow.
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WordNet (r) 3.0 (2006):

aggravating
    adj 1: making worse [syn: aggravating, exacerbating,
           exasperating]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "aggravating":
   aggravative, annoying, bothering, bothersome, contentious,
   disturbing, exasperating, exasperative, galling, harassing,
   importunate, importune, irking, irksome, irritating, pesky,
   pestering, pestiferous, pestilent, pestilential, plaguesome,
   plaguey, plaguing, provocative, provoking, teasing, tiresome,
   tormenting, troublesome, troubling, vexatious, vexing, wearisome,
   worrisome, worrying