croak vs fail

croak is a noun but fail is not a noun.

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

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

croak (verb)	fail (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	stop operating or functioning
make complaining remarks or noises under one's breath	deteriorate
utter a hoarse sound, like a raven	prove insufficient
	disappoint, prove undependable to; abandon, forsake
	become bankrupt or insolvent; fail financially and close
	be unsuccessful
	fail to get a passing grade
	fail to do something; leave something undone
	judge unacceptable
	be unable
	fall short in what is expected