Definitions
make complaining remarks or noises under one's breath
Word origin
From Middle English murmur, murmor, murmour, from Old French murmure (modern French murmure), from Latin murmur (“murmur, humming, muttering, roaring, growling, rushing etc.”).
Used in a sentence
“The delightful murmur of water running over pebbles is heard a few yards off”
“1979: A translation of the Eclogues by Paul Alpers The windy murmur of the breeze subsides.”
“A murmur arose from the audience.”
Source: Wiktionary, CC BY-SA 4.0
Used as a crossword answer2 curated clues
01“Low sound”6 letters
02“Low continuous sound”6 letters
Not quite right?
"Search similar patterns."
M_____