The Collaborative International Dictionary of English v.0.48:

Difficulty \Dif"fi*cul*ty\, n.; pl. Difficulties. [L.
   difficultas, fr. difficilis difficult; dif- = dis- + facilis
   easy: cf. F. difficult['e]. See Facile.]
   1. The state of being difficult, or hard to do; hardness;
      arduousness; -- opposed to easiness or facility; as,
      the difficulty of a task or enterprise; a work of
      difficulty.
      [1913 Webster]

            Not being able to promote them [the interests of
            life] on account of the difficulty of the region.
                                                  --James Byrne.
      [1913 Webster]

   2. Something difficult; a thing hard to do or to understand;
      that which occasions labor or perplexity, and requires
      skill and perseverance to overcome, solve, or achieve; a
      hard enterprise; an obstacle; an impediment; as, the
      difficulties of a science; difficulties in theology.
      [1913 Webster]

            They lie under some difficulties by reason of the
            emperor's displeasure.                --Addison.
      [1913 Webster]

   3. A controversy; a falling out; a disagreement; an
      objection; a cavil.
      [1913 Webster]

            Measures for terminating all local difficulties.
                                                  --Bancroft.
      [1913 Webster]

   4. Embarrassment of affairs, especially financial affairs; --
      usually in the plural; as, to be in difficulties.
      [1913 Webster]

            In days of difficulty and pressure.   --Tennyson.

   Syn: Impediment; obstacle; obstruction; embarrassment;
        perplexity; exigency; distress; trouble; trial;
        objection; cavil. See Impediment.
        [1913 Webster]

WordNet (r) 3.0 (2006):

difficulty
    n 1: an effort that is inconvenient; "I went to a lot of
         trouble"; "he won without any trouble"; "had difficulty
         walking"; "finished the test only with great difficulty"
         [syn: trouble, difficulty]
    2: a factor causing trouble in achieving a positive result or
       tending to produce a negative result; "serious difficulties
       were encountered in obtaining a pure reagent"
    3: a condition or state of affairs almost beyond one's ability
       to deal with and requiring great effort to bear or overcome;
       "grappling with financial difficulties"
    4: the quality of being difficult; "they agreed about the
       difficulty of the climb" [syn: difficulty, difficultness]
       [ant: ease, easiness, simpleness, simplicity]