blenny vs blennioid

blenny and blennioid both are nouns.

Word	Noun	Adjective	Verb	Adverb
blenny	Yes	No	No	No
blennioid	Yes	No	No	No

As nouns, blennioid is a hypernym of blenny; that is, blennioid is a word with a broader meaning than blenny:

blenny: small usually scaleless fishes with comb-like teeth living about rocky shores; are territorial and live in holes between rocks
blennioid: elongated mostly scaleless marine fishes with large pectoral fins and reduced pelvic fins

Other hypernyms of blenny include blennioid fish.

blenny (noun)	blennioid (noun)
small usually scaleless fishes with comb-like teeth living about rocky shores; are territorial and live in holes between rocks	elongated mostly scaleless marine fishes with large pectoral fins and reduced pelvic fins