\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`\, a.
Silent and idle. [Colloq.]
      Boys can't sit mum-chance always.        --J. H. Ewing.