The capital of Qatar (4)
I believe the answer is:
doha
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the capital of qatar</span>' is the definition.<br/ ><span class="explanation-format__explanation">('Doha' can be a synonym of 'capital of qatar')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for doha that I've seen before include "Gulf resort" , "Capital of Qatar" , "Trade round" .)