v. & n.
--v.
1. intr. speak low in a barely audible manner.
2 intr. (often foll. by against, at) murmur or grumble about.
3 tr. utter (words etc.) in a low tone.
4 tr. say in secret.
--n.
1. muttered words or sounds.
2 muttering.
Derivatives:
mutterer n. mutteringly adv.
Etymology: ME, rel. to MUTE