Source : Webster's Revised Unabridged Dictionary (1913)

Mum-chance \Mum"-chance`\, n.
   1. A game of hazard played with cards in silence. [Obs. or
      Prov. Eng.] --Decker.

   2. A silent, stupid person. [Prov. Eng.] --Halliwell.

Mum-chance \Mum"-chance`\, a.
   Silent and idle. [Colloq.]

         Boys can't sit mum-chance always.        --J. H. Ewing.