To make a low, hoarse noise in the throat, as a frog, a raven, or a crow; hence, to make any hoarse, dismal sound.

To complain; especially, to grumble; to forebode evil; to utter complaints or forebodings habitually.

To utter in a low, hoarse voice; to announce by croaking; to forebode; as, to croak disaster.

The coarse, harsh sound uttered by a frog or a raven, or a like sound.

a harsh hoarse utterance (as of a frog)

utter a hoarse sound, like a raven

make complaining remarks or noises under one's breath; "she grumbles when she feels overworked"