club soda vs soda water

club soda and soda water both are nouns.

Word	Noun	Adjective	Verb	Adverb
club soda	Yes	No	No	No
soda water	Yes	No	No	No

As nouns, club soda and soda water are synonyms defined as:

club soda and soda water: effervescent beverage artificially charged with carbon dioxide

Other synonyms of club soda include carbonated water, seltzer, sparkling water.

club soda (noun)	soda water (noun)
effervescent beverage artificially charged with carbon dioxide	effervescent beverage artificially charged with carbon dioxide
	a sweet drink containing carbonated water and flavoring