dolphin vs sea wolf

dolphin and sea wolf both are nouns.

Word	Noun	Adjective	Verb	Adverb
dolphin	Yes	No	No	No
sea wolf	Yes	No	No	No

As nouns, sea wolf is a hyponym of dolphin; that is, sea wolf is a word with a more specific, narrower meaning than dolphin:

dolphin: any of various small toothed whales with a beaklike snout; larger than porpoises
sea wolf: predatory black-and-white toothed whale with large dorsal fin; common in cold seas

dolphin (noun)	sea wolf (noun)
any of various small toothed whales with a beaklike snout; larger than porpoises	predatory black-and-white toothed whale with large dorsal fin; common in cold seas
large slender food and game fish widely distributed in warm seas (especially around Hawaii)