The Collaborative International Dictionary of English v.0.48:

Sham \Sham\, v. t. [imp. & p. p. Shammed; p. pr. & vb. n.
   Shamming.]
   1. To trick; to cheat; to deceive or delude with false
      pretenses.
      [1913 Webster]

            Fooled and shammed into a conviction. --L'Estrange.
      [1913 Webster]

   2. To obtrude by fraud or imposition. [R.]
      [1913 Webster]

            We must have a care that we do not . . . sham
            fallacies upon the world for current reason.
                                                  --L'Estrange.
      [1913 Webster]

   3. To assume the manner and character of; to imitate; to ape;
      to feign.
      [1913 Webster]

   To sham Abram or To sham Abraham, to feign sickness; to
      malinger. Hence a malingerer is called, in sailors' cant,
      Sham Abram, or Sham Abraham.
      [1913 Webster]