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.