Saint-John's-bread vs locust bean

Saint-John's-bread and locust bean both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint-John's-bread	Yes	No	No	No
locust bean	Yes	No	No	No

Saint-John's-bread (noun)	locust bean (noun)
powder from the ground seeds and pods of the carob tree; used as a chocolate substitute	long pod containing small beans and sweetish edible pulp; used as animal feed and source of a chocolate substitute