Spelunker's spot (4)
I believe the answer is:
cave
'spelunker's spot' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cave that I've seen before include "Hollow in a cliff or underground" , "Natural underground space" , "Large grotto" , "Aladdin, Fingal, had one" , "Natural underground chamber" .)