(1):
(v. i.) To make a low continued noise, like the hum of bees, a stream of water, distant waves, or the wind in a forest.
(2):
(v. t.) To utter or give forth in low or indistinct words or sounds; as, to murmur tales.
(3):
(v. i.) A complaint half suppressed, or uttered in a low, muttering voice.
(4):
(v. i.) To utter complaints in a low, half-articulated voice; to feel or express dissatisfaction or discontent; to grumble; - often with at or against.
(5):
(v. i.) A low, confused, and indistinct sound, like that of running water.