percoidean vs acanthopterygian

percoidean and acanthopterygian both are nouns.

Word	Noun	Adjective	Verb	Adverb
percoidean	Yes	No	No	No
acanthopterygian	Yes	No	No	No

As nouns, acanthopterygian is a hypernym of percoidean; that is, acanthopterygian is a word with a broader meaning than percoidean:

percoidean: any of numerous spiny-finned fishes of the order Perciformes
acanthopterygian: a teleost fish with fins that are supported by sharp inflexible rays

Other hypernyms of percoidean include spiny-finned fish.

percoidean (noun)	acanthopterygian (noun)
any of numerous spiny-finned fishes of the order Perciformes	a teleost fish with fins that are supported by sharp inflexible rays