<p><strong>Noun</strong></p><ul><li>a low, continuous sound, as of a brook, the wind, or trees, or of low, indistinct voices.</li><li>foolish or meaningless chatter; prattle: the constant babbling of idle gossips.</li><li>the random production of meaningless vocal sounds characteristic of infants around the age of three months.</li><li>an abnormal sound heard on listening to the heart, usually through a stethoscope, produced by the blood passing through deformed cardiac valves.</li><li>a voice quality in which vibration of the vocal cords is accompanied by the escape of a great deal of air, as in the (h) of ahead; breathy voice.</li></ul><p><strong>Verb</strong></p><ul><li>(used without object) to make a low or indistinct sound, especially continuously.</li><li>to speak in a low tone or indistinctly.</li><li>to complain in a low tone or in private.</li></ul><p><strong>Synonyms</strong></p><ul><li>grouse</li></ul><p><strong>Verb</strong></p><ul><li>(used with object) to sound by murmurs.</li><li>to utter in a low tone: He murmured a threat as he left the room.</li></ul>