mutter

mutter is a   Verb

Definition:

[1] To utter words indistinctly or with a low voice and lips partly closed; esp., to utter indistinct complains 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 lightings flash, the muttering thunder rolls. Pope.

Synonyms: