boater vs canoeist

boater and canoeist both are nouns.

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

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

Other hyponyms of boater include paddler, ferryman, gondolier, gondoliere, rower, punter.

boater (noun)	canoeist (noun)
a stiff hat made of straw with a flat crown	someone paddling a canoe
someone who drives or rides in a boat