Chief city (7)
I believe the answer is:
capital
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">chief city</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for capital that I've seen before include "A country's main city" , "It's jolly good in the great city" , "Fantastic!" , "source of profit" , "Finances" .)