bloodsucker vs annelid worm

bloodsucker and annelid worm both are nouns.

Word	Noun	Adjective	Verb	Adverb
bloodsucker	Yes	No	No	No
annelid worm	Yes	No	No	No

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

bloodsucker: carnivorous or bloodsucking aquatic or terrestrial worms typically having a sucker at each end
annelid worm: worms with cylindrical bodies segmented both internally and externally

Other hypernyms of bloodsucker include annelid, segmented worm.

bloodsucker (noun)	annelid worm (noun)
carnivorous or bloodsucking aquatic or terrestrial worms typically having a sucker at each end	worms with cylindrical bodies segmented both internally and externally