Country on the Persian Gulf (6)
(Other definitions for kuwait that I've seen before include "Country invaded by Iraq" , "monarchy" , "nation" , "Gulf War liberated it, 1991" , "Arab kingdom, major source of oil" .)
'country on the persian gulf' 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 "Tehran's country" , "Country where the official language is Farsi" , "Formerly Persia" , "Modern-day Persia" , "Iraq's neighbour" .)