Grumble Mumble 

verb - it is when a person shakes his/her head looking downward with a melancholy look on his/her face while making a soft grunting sigh

John: Why are you so lame?
Sunny: *grumble mumbles*

Grumble Mumble by bapsiboy February 19, 2015

mumble-grumble

the need to take a massive intense shit

ive been holding this mumble-grumble all day.

mumble-grumble by theinventorofthemumble-grumble September 20, 2012

Mumbly Grumbly 

Term used to describe someone who complains, bitches and moans all the time but does it in a low 'mumbled' voice, and in low, run-on sentences so you can't understand what they are saying.
Usually, but not always, limited to grumpy old men.

That old dude looks mad, and keeps mumbling something, but I can't understand him.
Yeah that's old man Withers...he's always all Mumbly Grumbly.

Mumbly Grumbly by phoenixxx70 May 14, 2010

Grumblebumble 

This term is used when there people crowding you when you would like not, so you use this word- GRUMBLEBUMBLE - following another word that you would like. This will make people leave because they won't know what to think.

Person-John, lets annoy this fat kid! Okay!
other people start coming over
You-Grumblebumble- Dinkdawtear
they leave

Grumblebumble by Bjarnyie Dot Com June 28, 2004