Source : Webster's Revised Unabridged Dictionary (1913)

Trump \Trump\, v. i. [imp. & p. p. {Trumped}; p. pr. & vb. n.
   {Trumping}.]
   To play a trump card when one of another suit has been led.

Source : WordNet®

trumping
     n : the act of taking a trick with a trump when unable to follow
         suit [syn: {ruff}]