Definition – to talk in a low inarticulate way: mutter

Chunter, like bebop and bisbigliando, is a word of imitative origin. In use since the 16th century, it is one of a fine number of synonyms the English language possesses for “mutter.” Should you need additional obscure ways of saying mutter or grumble you may use channer, mammer, or [mussitate]/dictionary/mussitate).