croak vs cronk

croak is a noun but cronk is not a noun.

Word	Noun	Adjective	Verb	Adverb
croak	Yes	No	Yes	No
cronk	No	No	Yes	No

As verbs, croak and cronk are synonyms defined as:

croak (noun)	cronk (noun)
a harsh hoarse utterance (as of a frog)

croak (verb)	cronk (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	utter a hoarse sound, like a raven
make complaining remarks or noises under one's breath	cry like a goose
utter a hoarse sound, like a raven