natator vs surfboarder

natator and surfboarder both are nouns.

Word	Noun	Adjective	Verb	Adverb
natator	Yes	No	No	No
surfboarder	Yes	No	No	No

As nouns, surfboarder is a hyponym of natator; that is, surfboarder is a word with a more specific, narrower meaning than natator:

Other hyponyms of natator include floater, aquanaut, skin-diver, surfer.

natator (noun)	surfboarder (noun)
a person who travels through the water by swimming	someone who engages in surfboarding