The Croatian capital (6)
I believe the answer is:
zagreb
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the croatian capital</span>' is the definition.<br/ ><span class="explanation-format__explanation">(capital of Croatia)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for zagreb that I've seen before include "Capital city of Croatia" , "on River Sava" , "Croatia's capital city" , "Croatian city" , "European capital" .)