kingfish vs croaker

kingfish and croaker both are nouns.

Word	Noun	Adjective	Verb	Adverb
kingfish	Yes	No	No	No
croaker	Yes	No	No	No

As nouns, croaker is a hypernym of kingfish; that is, croaker is a word with a broader meaning than kingfish:

kingfish (noun)	croaker (noun)
any of several food and game fishes of the drum family indigenous to warm Atlantic waters of the North American coast	any of several fishes that make a croaking noise
large edible mackerel of temperate United States coastal Atlantic waters	the lean flesh of a saltwater fish caught along Atlantic coast of southern U.S.
small silvery marine food fish found off California
large game fish of Australia and New Zealand
the lean flesh of any of several fish caught off the Atlantic coast of the United States