grumble vs grumbling

grumble and grumbling both are nouns.

Word	Noun	Adjective	Verb	Adverb
grumble	Yes	No	Yes	No
grumbling	Yes	Yes	No	No

As nouns, grumble and grumbling are synonyms defined as:

Other synonyms of grumble include murmur, murmuring, mutter, muttering.

As nouns, grumble and grumbling are synonyms defined as:

Other synonyms of grumble include rumble, rumbling.

grumble (noun)	grumbling (noun)
a complaint uttered in a low and indistinct tone	a complaint uttered in a low and indistinct tone
a loud low dull continuous noise	a loud low dull continuous noise

grumble (adjective)	grumbling (adjective)
	continuous full and low-pitched throbbing sound

grumble (verb)	grumbling (verb)
make complaining remarks or noises under one's breath
show one's unhappiness or critical attitude
to utter or emit low dull rumbling sounds
make a low noise