The Collaborative International Dictionary of English v.0.48:

Counterfeit \Coun"ter*feit\ (koun"t?r-f?t), a. [F. contrefait,
   p. p. of contrefaire to counterfeit; contre (L. contra) +
   faire to make, fr. L. facere. See Counter, adv., and
   Fact.]
   [1913 Webster]
   1. Representing by imitation or likeness; having a
      resemblance to something else; portrayed.
      [1913 Webster]

            Look here upon this picture, and on this
            The counterfeit presentment of two brothers. --Shak.
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   2. Fabricated in imitation of something else, with a view to
      defraud by passing the false copy for genuine or original;
      as, counterfeit antiques; counterfeit coin. "No
      counterfeit gem." --Robinson (More's Utopia).
      [1913 Webster]

   3. Assuming the appearance of something; false; spurious;
      deceitful; hypocritical; as, a counterfeit philanthropist.
      "An arrant counterfeit rascal." --Shak.

   Syn: Forged; fictitious; spurious; false.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Counterfeit \Coun"ter*feit\, n.
   1. That which resembles or is like another thing; a likeness;
      a portrait; a counterpart.
      [1913 Webster]

            Thou drawest a counterfeit
            Best in all Athens.                   --Shak.
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            Even Nature's self envied the same,
            And grudged to see the counterfeit should shame
            The thing itself.                     --Spenser.
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   2. That which is made in imitation of something, with a view
      to deceive by passing the false for the true; as, the bank
      note was a counterfeit.
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            Never call a true piece of gold a counterfeit.
                                                  --Shak.
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            Some of these counterfeits are fabricated with such
            exquisite taste and skill, that it is the
            achievement of criticism to distinguish them from
            originals.                            --Macaulay.
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   3. One who pretends to be what he is not; one who personates
      another; an impostor; a cheat.
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            I fear thou art another counterfeit;
            And yet, in faith, thou bear'st thee like a king.
                                                  --Shak.
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The Collaborative International Dictionary of English v.0.48:

Counterfeit \Coun"ter*feit\, v. t. [imp. & p. p.
   Counterfeited; p. pr. & vb. n. Counterfeiting.]
   1. To imitate, or put on a semblance of; to mimic; as, to
      counterfeit the voice of another person.
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            Full well they laughed with counterfeited glee
            At all his jokes, for many a joke had he.
                                                  --Goldsmith.
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   2. To imitate with a view to deceiving, by passing the copy
      for that which is original or genuine; to forge; as, to
      counterfeit the signature of another, coins, notes, etc.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Counterfeit \Coun"ter*feit\, v. i.
   1. To carry on a deception; to dissemble; to feign; to
      pretend.
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            The knave counterfeits well; a good knave. --Shak.
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   2. To make counterfeits.
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WordNet (r) 3.0 (2006):

counterfeit
    adj 1: not genuine; imitating something superior; "counterfeit
           emotion"; "counterfeit money"; "counterfeit works of
           art"; "a counterfeit prince" [syn: counterfeit,
           imitative] [ant: echt, genuine]
    n 1: a copy that is represented as the original [syn:
         counterfeit, forgery]
    v 1: make a copy of with the intent to deceive; "he faked the
         signature"; "they counterfeited dollar bills"; "She forged
         a Green Card" [syn: forge, fake, counterfeit]