Former Persian ruler (4)
I believe the answer is:
shah
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">former persian ruler</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for shah that I've seen before include "Former Persian title" , "King of Persia" , "Former ruler of Iran" , "Sovereign ousted in 1979" , "Former Persian ruler" .)