It resembles a series of deep, half-smothered detonations linked together by querulous gruntle.
"Reminiscences of a South African Pioneer"
W. C. Scully
And the noise that it sent out was strange and slow, and it did seem to gruntle gently unto itself in that lonesome hollow, as that it had made a long and quiet grumbling there, through Eternity.
"The Night Land"
William Hope Hodgson
Like one of them he would gruntle and make an ugly noise, according as he was offended or pleased, or would have anything done.
"Bunyan"
James Anthony Froude