sailor vs boater

sailor and boater both are nouns.

Word	Noun	Adjective	Verb	Adverb
sailor	Yes	No	No	No
boater	Yes	No	No	No

As nouns, sailor and boater are synonyms defined as:

Other synonyms of sailor include leghorn, Panama, Panama hat, skimmer, straw hat.

sailor (noun)	boater (noun)
a stiff hat made of straw with a flat crown	a stiff hat made of straw with a flat crown
any member of a ship's crew	someone who drives or rides in a boat
a serviceman in the navy