waterman vs paddler

waterman and paddler both are nouns.

Word	Noun	Adjective	Verb	Adverb
waterman	Yes	No	No	No
paddler	Yes	No	No	No

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

Other hyponyms of waterman include canoeist, ferryman, gondolier, gondoliere, rower, punter.

waterman (noun)	paddler (noun)
someone who drives or rides in a boat	someone paddling a canoe