Meaning

noun a soft indistinct utterance

verb talk indistinctly; usually in a low voice

verb grind with the gums; chew without teeth and with great difficulty

originFrom Middle English momelen, a frequentative of mum (sense 3) (“silent”). Compare German mümmeln, Middle Dutch mommelen and Dutch mompelen. Perhaps related to Norwegian Nynorsk mumpa (“to gum, to chew without teeth”).

Etymology from Wiktionary, CC BY-SA 3.0