Country on the Caspian (4)
I believe the answer is:
iran
'country on the caspian' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for iran that I've seen before include "Country of western Asia" , "Middle East country" , "Country where ayatollahs replaced a shah" , "Modern name for Persia" , "Farsi-speaking country" .)