croak vs kvetch

croak and kvetch both are nouns.

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

As verbs, kvetch is a hypernym of croak; that is, kvetch is a word with a broader meaning than croak:

Other hypernyms of croak include complain, kick, plain, quetch, sound off.

croak (noun)	kvetch (noun)
a harsh hoarse utterance (as of a frog)	(Yiddish) a nagging complaint
	(Yiddish) a constant complainer

croak (verb)	kvetch (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	express complaints, discontent, displeasure, or unhappiness
make complaining remarks or noises under one's breath
utter a hoarse sound, like a raven