water sport vs surfing

water sport and surfing both are nouns.

Word	Noun	Adjective	Verb	Adverb
water sport	Yes	No	No	No
surfing	Yes	No	No	No

As nouns, surfing is a hyponym of water sport; that is, surfing is a word with a more specific, narrower meaning than water sport:

water sport: sports that involve bodies of water
surfing: the sport of riding a surfboard toward the shore on the crest of a wave

Other hyponyms of water sport include swim, swimming, surfboarding, surfriding, water-skiing.

water sport (noun)	surfing (noun)
sports that involve bodies of water	the sport of riding a surfboard toward the shore on the crest of a wave