[1] : The Collaborative International Dictionary of English v.0.48

irritate \ir"ritate\, v. t. imp.  p. p. irritated; p. pr. 
   vb. n. irritating. l. irritatus, p. p. of irritare. of
   doubtful origin.
   1913 webster
   1. to increase the action or violence of; to heighten
      excitement in; to intensify; to stimulate.
      1913 webster

            cold maketh the spirits vigorous and irritateth
            them.                                 --bacon.
      1913 webster

   2. to excite anger or displeasure in; to provoke; to tease;
      to exasperate; to annoy; to vex; as, the insolence of a
      tyrant irritates his subjects.
      1913 webster

            dismiss the man, nor irritate the god:
            prevent the rage of him who reigns above. --pope.
      1913 webster

   3. physiol. to produce irritation in; to stimulate; to
      cause to contract. see irritation, n., 2.
      1913 webster

   4. med. to make morbidly excitable, or oversensitive; to
      fret; as, the skin is irritated by friction; to irritate a
      wound by a coarse bandage.

   syn: to fret; inflame; excite; provoke; tease; vex;
        exasperate; anger; incense; enrage.

   usage: to irritate, provoke, exasperate. these words
          express different stages of excited or angry feeling.
          irritate denotes an excitement of quick and slightly
          angry feeling which is only momentary; as, irritated
          by a hasty remark. to provoke implies the awakening of
          some open expression of decided anger; as, a provoking
          insult. exasperate denotes a provoking of anger at
          something unendurable. whatever comes across our
          feelings irritates; whatever excites anger provokes;
          whatever raises anger to a high point exasperates.
          "susceptible and nervous people are most easily
          irritated; proud people are quickly provoked; hot and
          fiery people are soonest exasperated." --crabb.
          1913 webster
see also:
irritated irritating irritation irritate provoke exasperate 

[2] : The Collaborative International Dictionary of English v.0.48

irritating \irritating\ adj.
   1. causing annoyance.

   syn: annoying, galling, chafing, nettlesome, pesky,
        pestiferous, pestilent, plaguy, plaguey, teasing,
        vexatious, vexing.
        wordnet 1.5 +pjc

   2. causing irritation of living tissue; -- used of physical
      stimuli.

   syn: irritant, irritative.
        wordnet 1.5 +pjc

   3. causing pain or physical discomfort; as, an irritating
      burr under his stocking.

   syn: painful.
        wordnet 1.5

[3] : WordNet (r) 2.0

irritating
     adj 1: causing irritation or annoyance; "tapping an annoying rhythm
            on his glass with his fork"; "aircraft noise is
            particularly bothersome near the airport"; "found it
            galling to have to ask permission"; "an irritating
            delay"; "nettlesome paperwork"; "a pesky mosquito";
            "swarms of pestering gnats"; "a plaguey newfangled
            safety catch"; "a teasing and persistent thought
            annoyed him"; "a vexatious child"; "it is vexing to
            have to admit you are wrong" syn: annoying, bothersome,
             galling, nettlesome, pesky, pestering, pestiferous,
             plaguy, plaguey, teasing, vexatious, vexing
     2: used of physical stimuli serving to stimulate or excite;
        "an irritative agent" syn: irritative
     3: causing physical discomfort; "bites of black flies are more
        than irritating; they can be very painful" syn: painful
see also:
annoying bothersome galling nettlesome pesky pestering 
pestiferous plaguy plaguey teasing vexatious 
vexing irritative painful 

[4] : Moby Thesaurus II by Grady Ward, 1.0

69 moby thesaurus words for "irritating":
   acerbic, acid, acrid, aggravating, aggravative, annoying, asperous,
   astringent, biting, bitter, bothering, bothersome, caustic,
   chafing, contentious, cutting, disturbing, escharotic,
   exasperating, exasperative, fretting, galling, grating, grinding,
   harassing, harsh, importunate, importune, irking, irksome,
   irritant, irritative, keen, mordant, nose-tickling, penetrating,
   pesky, pestering, pestiferous, pestilent, pestilential, piercing,
   piquant, plaguesome, plaguey, plaguing, poignant, provocative,
   provoking, pungent, rasping, rough, scratchy, severe, sharp, sour,
   stinging, teasing, tiresome, tormenting, trenchant, troublesome,
   troubling, vexatious, vexing, vitriolic, wearisome, worrisome,
   worrying

Irritating >> I Words
Irritating, definition of term: Irritating
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