hyperdactyly vs polydactyly

hyperdactyly and polydactyly both are nouns.

Word	Noun	Adjective	Verb	Adverb
hyperdactyly	Yes	No	No	No
polydactyly	Yes	No	No	No

As nouns, hyperdactyly and polydactyly are synonyms defined as:

hyperdactyly and polydactyly: birth defect characterized by the presence of more than the normal number of fingers or toes

hyperdactyly (noun)	polydactyly (noun)
birth defect characterized by the presence of more than the normal number of fingers or toes	birth defect characterized by the presence of more than the normal number of fingers or toes