murmurer

noun

1. a low, indistinct, continuous sound, as of a stream, far-off voices, etc.
2. a mumbled or muttered complaint
3. Med. any abnormal sound heard by auscultation, esp. of the heart

Etymology: ME murmure < OFr < L, a murmur, roar, muttering < IE echoic base *mormor-, *murmur- > Sans marmara-, Gr mormurein

intransitive verb

1. to make a murmur
2. to mumble or mutter a complaint

transitive verb