croak vs stifle

croak and stifle both are nouns.

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

As verbs, stifle is a hyponym of croak; that is, stifle is a word with a more specific, narrower meaning than croak:

croak: pass from physical life and lose all bodily attributes and functions necessary to sustain life
stifle: be asphyxiated; die from lack of oxygen

Other hyponyms of croak include abort, asphyxiate, suffocate, buy it, pip out, drown, predecease, famish, starve, fall, succumb, yield.

croak (noun)	stifle (noun)
a harsh hoarse utterance (as of a frog)	joint between the femur and tibia in a quadruped; corresponds to the human knee

croak (verb)	stifle (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	suppress or constrain so as to lessen in intensity
make complaining remarks or noises under one's breath	be asphyxiated; die from lack of oxygen
utter a hoarse sound, like a raven	suppress in order to conceal or hide
	impair the respiration of or obstruct the air passage of