List of muttering synonyms and muttering related words.
aspiration, bated breath, beefing, bellyaching, bitching, breath, breathy voice, complaining, complaintful, crabbing, crabby, cranky, croaking, disappointed, discontented, disgruntled, displeased, dissatisfied, drone, droning, envious, exhalation, faultfinding, gabble, gibber, gibbering, griping, grouchy, grousing, growling, grumbling, jabber, jibber, little voice, low voice, malcontent, malcontented, maundering, mouthing, mumble, mumbling, murmur, murmuration, murmuring, murmurish, murmurous, mutter, out of humor, peevish, petulant, querulant, querulous, rebellious, resentful, restive, restless, rustling, sigh, soft voice, stage whisper, still small voice, sulky, susurrant, susurration, susurrous, susurrus, unaccepting, unaccommodating, underbreath, undertone, uneasy, unfulfilled, ungratified, unhappy, unsatisfied, whiny, whisper, whispering, whispery