spelunker

noun2

1. •
   (US, Canada) One who explores caves; one who spelunks.
2. •
   (disapproving) An amateur or inadequately prepared caver.

   • But the scariest of all’s the witless caver; Spelunker is the name that he goes by. He caves alone with just one light, A worn-out rope, and boots too tight, Looking for a cave in which to die. — 2003