The Collaborative International Dictionary of English v.0.48:

Annoyance \An*noy"ance\, n. [OF. anoiance, anuiance.]
   1. The act of annoying, or the state of being annoyed;
      molestation; vexation; annoy.
      [1913 Webster]

            A deep clay, giving much annoyance to passengers.
                                                  --Fuller.
      [1913 Webster]

            For the further annoyance and terror of any besieged
            place, they would throw into it dead bodies.
                                                  --Wilkins.
      [1913 Webster]

   2. That which annoys.
      [1913 Webster]

            A grain, a dust, a gnat, a wandering hair,
            Any annoyance in that precious sense. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

annoyance
    n 1: the psychological state of being irritated or annoyed [syn:
         irritation, annoyance, vexation, botheration]
    2: anger produced by some annoying irritation [syn: annoyance,
       chafe, vexation]
    3: an unpleasant person who is annoying or exasperating [syn:
       aggravator, annoyance]
    4: something or someone that causes trouble; a source of
       unhappiness; "washing dishes was a nuisance before we got a
       dish washer"; "a bit of a bother"; "he's not a friend, he's
       an infliction" [syn: annoyance, bother, botheration,
       pain, infliction, pain in the neck, pain in the ass]
    5: the act of troubling or annoying someone [syn: annoyance,
       annoying, irritation, vexation]