#underwater_diver__diver__frogman  someone who works underwater
  supertype:  explorer__adventurer  someone who travels into little known regions (especially for some scientific purpose)
  subtype:  deep-sea_diver  a diver in the deeper parts of the sea
  subtype:  pearl_diver__pearldiver__pearler  a diver who searches for molluscs containing pearls
  subtype:  scuba_diver__scubadiver  an underwater diver who uses scuba gear

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