frogman vs explorer

frogman and explorer both are nouns.

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

As nouns, explorer is a hypernym of frogman; that is, explorer is a word with a broader meaning than frogman:

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

Other hypernyms of frogman include adventurer.

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