Small picturesque cave (6)
I believe the answer is:
grotto
'small picturesque cave' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for grotto that I've seen before include "It's left on Dec 24 by Santa and his reindeer" , "Fancy cave" , "Cavern" , "Small cave as at Lourdes" , "(Imitation) cave" .)