explorer vs diver

explorer and diver both are nouns.

Word	Noun	Adjective	Verb	Adverb
explorer	Yes	No	No	No
diver	Yes	No	No	No

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

explorer: someone who travels into little known regions (especially for some scientific purpose)
diver: someone who works underwater

explorer (noun)	diver (noun)
someone who travels into little known regions (especially for some scientific purpose)	large somewhat primitive fish-eating diving bird of the Northern Hemisphere having webbed feet placed far back; related to the grebes
	someone who dives (into water)
	someone who works underwater