Land south of the Caspian Sea (4)
I believe the answer is:
iran
'land south of the caspian sea' 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 "Tehran is its capital" , "Country to east of Iraq" , "Persia today" , "Islamic republic on the Persian Gulf" , "Middle East country" .)