American crayfish vs crawfish

American crayfish and crawfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
American crayfish	Yes	No	No	No
crawfish	Yes	No	Yes	No

As nouns, crawfish is a hypernym of American crayfish; that is, crawfish is a word with a broader meaning than American crayfish:

Other hypernyms of American crayfish include crawdad, crawdaddy, crayfish.

American crayfish (noun)	crawfish (noun)
common large crayfishes of eastern North America	large edible marine crustacean having a spiny carapace but lacking the large pincers of true lobsters
	small freshwater decapod crustacean that resembles a lobster
	tiny lobster-like crustaceans usually boiled briefly

American crayfish (verb)	crawfish (verb)
	make a retreat from an earlier commitment or activity