WordWeb Online

1. Indistinct enunciation
    
2. Ineffectual chewing (as if without teeth)
   - gumming

1. Talk indistinctly; usually in a low voice
   - mutter, maunder, mussitate
    
2. Grind with the gums; chew without teeth and with great difficulty
   "the old man had no teeth left and mumbled his food";
   - gum

Derived forms: mumblings

Type of: chew, chewing, diction, enunciation, jaw [informal], manducate, manduction, masticate, mastication, mouth, speak, talk, utter, verbalise [Brit], verbalize

Encyclopedia: Mumble