hamadryad vs cobra

hamadryad and cobra both are nouns.

Word	Noun	Adjective	Verb	Adverb
hamadryad	Yes	No	No	No
cobra	Yes	No	No	No

As nouns, cobra is a hypernym of hamadryad; that is, cobra is a word with a broader meaning than hamadryad:

hamadryad: large cobra of southeastern Asia and the East Indies; the largest venomous snake; sometimes placed in genus Naja
cobra: venomous Asiatic and African elapid snakes that can expand the skin of the neck into a hood

hamadryad (noun)	cobra (noun)
large cobra of southeastern Asia and the East Indies; the largest venomous snake; sometimes placed in genus Naja	venomous Asiatic and African elapid snakes that can expand the skin of the neck into a hood
the nymph or spirit of a particular tree