The Collaborative International Dictionary of English v.0.48:

Confidence \Con"fi*dence\, n. [L. confidentia firm trust in,
   self-confidence: cf. F. confidence.]
   1. The act of confiding, trusting, or putting faith in;
      trust; reliance; belief; -- formerly followed by of, now
      commonly by in.
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            Society is built upon trust, and trust upon
            confidence of one another's integrity. --South.
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            A cheerful confidence in the mercy of God.
                                                  --Macaulay.
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   2. That in which faith is put or reliance had.
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            The Lord shall be thy confidence.     --Prov. iii.
                                                  26.
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   3. The state of mind characterized by one's reliance on
      himself, or his circumstances; a feeling of
      self-sufficiency; such assurance as leads to a feeling of
      security; self-reliance; -- often with self prefixed.
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            Your wisdom is consumed in confidence;
            Do not go forth to-day.               --Shak.
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            But confidence then bore thee on secure
            Either to meet no danger, or to find
            Matter of glorious trial.             --Milton.
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   4. Private conversation; (pl.) secrets shared; as, there were
      confidences between them.
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            Sir, I desire some confidence with you. --Shak.
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   Confidence game, any swindling operation in which advantage
      is taken of the confidence reposed by the victim in the
      swindler; several swindlers often work together to create
      the illusion of truth; -- also called con game.

   Confidence man, a swindler.

   To take into one's confidence, to admit to a knowledge of
      one's feelings, purposes, or affairs.

   Syn: Trust; assurance; expectation; hope.
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              I am confident that very much be done. --Boyle.
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   2. Trustful; without fear or suspicion; frank; unreserved.
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            Be confident to speak, Northumberland;
            We three are but thyself.             --Shak.
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   3. Having self-reliance; bold; undaunted.
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            As confident as is the falcon's flight
            Against a bird, do I with Mowbray fight. --Shak.
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   4. Having an excess of assurance; bold to a fault;
      dogmatical; impudent; presumptuous.
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            The fool rageth and is confident.     --Prov. xiv.
                                                  16.
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   5. Giving occasion for confidence. [R.]
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            The cause was more confident than the event was
            prosperous.                           --Jer. Taylor.
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WordNet (r) 3.0 (2006):

confidence
    n 1: freedom from doubt; belief in yourself and your abilities;
         "his assurance in his superiority did not make him
         popular"; "after that failure he lost his confidence"; "she
         spoke with authority" [syn: assurance, self-assurance,
         confidence, self-confidence, authority, sureness]
    2: a feeling of trust (in someone or something); "I have
       confidence in our team"; "confidence is always borrowed,
       never owned" [ant: diffidence, self-distrust, self-
       doubt]
    3: a state of confident hopefulness that events will be
       favorable; "public confidence in the economy"
    4: a trustful relationship; "he took me into his confidence";
       "he betrayed their trust" [syn: confidence, trust]
    5: a secret that is confided or entrusted to another; "everyone
       trusted him with their confidences"; "the priest could not
       reveal her confidences"