roaster vs cook

roaster and cook both are nouns.

Word	Noun	Adjective	Verb	Adverb
roaster	Yes	No	No	No
cook	Yes	No	Yes	No

As nouns, cook is a hypernym of roaster; that is, cook is a word with a broader meaning than roaster:

roaster (noun)	cook (noun)
a special cooking pan for roasting	someone who cooks food
flesh of a large young chicken over 3 1/2 lb suitable for roasting
a cook who roasts food
a harsh or humorous critic (sometimes intended as a facetious compliment)

roaster (verb)	cook (verb)
	transform and make suitable for consumption by heating
	transform by heating
	prepare for eating by applying heat
	prepare a hot meal
	tamper, with the purpose of deception