lugworm vs polychete worm

lugworm and polychete worm both are nouns.

Word	Noun	Adjective	Verb	Adverb
lugworm	Yes	No	No	No
polychete worm	Yes	No	No	No

As nouns, polychete worm is a hypernym of lugworm; that is, polychete worm is a word with a broader meaning than lugworm:

lugworm: marine worms having a row of tufted gills along each side of the back; often used for fishing bait
polychete worm: chiefly marine annelids possessing both sexes and having paired appendages (parapodia) bearing bristles

Other hypernyms of lugworm include polychaete, polychaete worm, polychete.

lugworm (noun)	polychete worm (noun)
marine worms having a row of tufted gills along each side of the back; often used for fishing bait	chiefly marine annelids possessing both sexes and having paired appendages (parapodia) bearing bristles