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.
      [1913 Webster]

            Full well they laughed with counterfeited glee
            At all his jokes, for many a joke had he.
                                                  --Goldsmith.
      [1913 Webster]

   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]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "counterfeiting":
   coinage, coining, copying, emulation, fakery, following, forgery,
   hit-off, imitation, impersonation, imposture, impression, mimesis,
   mintage, mirroring, onomatopoeia, parody, plagiarism, plagiary,
   repetition, simulation, stamping, striking, takeoff