sea crawfish vs lobster

sea crawfish and lobster both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea crawfish	Yes	No	No	No
lobster	Yes	No	No	No

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

sea crawfish: large edible marine crustacean having a spiny carapace but lacking the large pincers of true lobsters
lobster: any of several edible marine crustaceans of the families Homaridae and Nephropsidae and Palinuridae

sea crawfish (noun)	lobster (noun)
large edible marine crustacean having a spiny carapace but lacking the large pincers of true lobsters	any of several edible marine crustaceans of the families Homaridae and Nephropsidae and Palinuridae
	flesh of a lobster