definition of
mutter

[1] #1 mutter v. [mumble, maunder, mussitate] talk indistinctly; usually in a low voice. wn

[2] #2 mutter v. [murmur, grumble, croak, gnarl] make complaining remarks or noises under one's breath; "she grumbles when she feels overworked". wn

[3] #3 mutter n. [muttering, murmur, murmuring, murmuration, mussitation] a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech. wn

[4] #4 mutter n. [grumble, grumbling, murmur, murmuring, muttering] a complaint uttered in a low and indistinct tone. wn