dactyl vs polydactylous

dactyl is a noun but polydactylous is not a noun.

Word	Noun	Adjective	Verb	Adverb
dactyl	Yes	No	No	No
polydactylous	No	Yes	No	No

dactyl (noun)	polydactylous (noun)
a finger or toe in human beings or corresponding body part in other vertebrates
a metrical unit with stressed-unstressed-unstressed syllables

dactyl (adjective)	polydactylous (adjective)
	of or relating to a person (or other vertebrate) having more than the normal number of digits