Land south of the Caspian (4)
I believe the answer is:
iran
'land south of the caspian' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for iran that I've seen before include "Country lying to south of Caspian sea" , "Country where ayatollahs replaced a shah" , "Former Persia" , "Persia some time ago" , "Country to east of Iraq" .)