Kuwait's ruler (4)
I believe the answer is:
emir
'kuwait's ruler' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for emir that I've seen before include "Muslim ruler stuck in mire" , "Arabic ruler" , "Ruler in the Middle East and mire" , "Title of various Muslim rulers" , "Title of various rulers; I'm ER (anag.)" .)