Race; hat (5)
I believe the answer is:
derby
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">race</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">hat</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(derby is a kind of hat)</span><br/ ><br/ ></span>
(Other definitions for derby that I've seen before include "Cathedral city on the River Derwent" , "Epsom horse race" , "Gracefully thin" , "Local game" , "Classic horse-race" .)