dolphin vs toothed whale

dolphin and toothed whale both are nouns.

Word	Noun	Adjective	Verb	Adverb
dolphin	Yes	No	No	No
toothed whale	Yes	No	No	No

As nouns, toothed whale is a hypernym of dolphin; that is, toothed whale is a word with a broader meaning than dolphin:

dolphin: any of various small toothed whales with a beaklike snout; larger than porpoises
toothed whale: any of several whales having simple conical teeth and feeding on fish etc.

dolphin (noun)	toothed whale (noun)
any of various small toothed whales with a beaklike snout; larger than porpoises	any of several whales having simple conical teeth and feeding on fish etc.
large slender food and game fish widely distributed in warm seas (especially around Hawaii)