Difference between Grumble and Muttering

GRUMBLE vs MUTTERING: NOUN

A rumour.
Something which is muttered
The sound made by one who mutters; grumbling; mumbling: as, an angry muttering.
A low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
A complaint uttered in a low and indistinct tone

To make a low, growling or rumbling noise, like a hungry stomach or certain animals.
To complain.
To utter in a grumbling fashion.
Make complaining remarks or noises under one's breath
Show one's unhappiness or critical attitude
Make a low noise
To utter or emit low dull rumbling sounds

To express in a grumbling discontented manner.
To rumble or growl.
To complain in a surly manner; mutter discontentedly.
To rumble; to make a low, harsh, and heavy sound; to mutter.
To growl; to snarl in deep tones.
To murmur or mutter with discontent; to make ill-natured complaints in a low voice and a surly manner.

Griping, Moan, Complain, Jones, Gnarl, Grouch, Croak, Rumble, Rumbling, Growl, Murmuring, Scold, Murmur, Muttering, Mutter

Cursing, Tutting, Mouthing, Tittered, Jabbered, Babbling, Smirking, Whispering, Murmuration, Speaking, Grumble, Murmur, Grumbling, Murmuring, Mumbling

Grousing, Whine, Griping, Moan, Jones, Gnarl, Grouch, Rumble, Rumbling, Growl, Murmuring, Scold, Murmur, Muttering, Mutter

Snickering, Cursing, Tutting, Mouthing, Tittered, Jabbered, Babbling, Smirking, Whispering, Speaking, Grumble, Murmur, Grumbling, Murmuring, Mumbling

Muttering under his breath, he ran frantically over the bridge.
Patient muttering to self as though answering an unseen person.
Use of this Kenny muttering signifies your bandanna to the.
And there was much muttering about him among the people.
Christopher Bradman As we first entered March and early muttering.
Then, muttering to himself, he headed for the living room.
George muttering unhappily to himself in the dining room.
He seemed to be muttering, his voice surprisingly clear.
Muttering under her breath, some kind of sissy.
Comptroller at Muttering the Soldiers, a Clerk or Secretary that writes down in what Condition every Thing is found at a Muttering.