Source : Webster's Revised Unabridged Dictionary (1913)

Trump \Trump\, v. t. [F. tromper to deceive, in OF., to blow a
   trumpet, se tromper de to mock. See {Trump} a trumpet.]
   1. To trick, or impose on; to deceive. [Obs.] ``To trick or
      trump mankind.'' --B. Jonson.

   2. To impose unfairly; to palm off.

            Authors have been trumped upon us.    --C. Leslie.

   {To trump up}, to devise; to collect with unfairness; to
      fabricate; as, to trump up a charge.