bather vs surfer

bather and surfer both are nouns.

Word	Noun	Adjective	Verb	Adverb
bather	Yes	No	No	No
surfer	Yes	No	No	No

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

Other hyponyms of bather include floater, aquanaut, skin-diver, surfboarder.

bather (noun)	surfer (noun)
a person who travels through the water by swimming	someone who engages in surfboarding
a person who takes a bath