Mut″ter (?), v. i. [imp. & p. p.Muttered (?); p. pr. & vb. n.Muttering.] [Prob. of imitative origin; cf. L. muttire, mutire.] 1. To utter words indistinctly or with a low voice and lips partly closed; esp., to utter indistinct complaints or angry expressions; to grumble; to growl.
Wizards that peep, and that mutter. Is. viii. 19.
Meantime your filthy foreigner will stare,
And mutter to himself. Dryden.
2. To sound with a low, rumbling noise.
Thick lightnings flash, the muttering thunder rolls. Pope.