Source : Webster's Revised Unabridged Dictionary (1913)

Mump \Mump\, v. t. [imp. & p. p. {Mumped}; p. pr. & vb. n.
   {Mumping}.]
   1. To utter imperfectly, brokenly, or feebly.

            Old men who mump their passion.       --Goldsmith.

   2. To work over with the mouth; to mumble; as, to mump food.

   3. To deprive of (something) by cheating; to impose upon.