velvet worm vs onychophoran

velvet worm and onychophoran both are nouns.

Word	Noun	Adjective	Verb	Adverb
velvet worm	Yes	No	No	No
onychophoran	Yes	No	No	No

As nouns, velvet worm and onychophoran are synonyms defined as:

velvet worm and onychophoran: any of numerous velvety-skinned wormlike carnivorous animals common in tropical forests having characteristics of both arthropods and annelid worms

Other synonyms of velvet worm include peripatus.

velvet worm (noun)	onychophoran (noun)
any of numerous velvety-skinned wormlike carnivorous animals common in tropical forests having characteristics of both arthropods and annelid worms	any of numerous velvety-skinned wormlike carnivorous animals common in tropical forests having characteristics of both arthropods and annelid worms