Uttering a low, harsh, guttural sound.

Foreboding evil; grumbling.

verb. Present participle of croak.

noun. a harsh hoarse utterance (as of a frog)

"It made them strong and willful, and it made them blind and disfigured, and it spurred them to sing strange guttural songs in croaking voices that haunted the American night."

croaking lizard  

utterance  vocalization  

antismoking  broking  choking  cloaking  coking  

foreboding  

croak