Clerical cap (7)
I believe the answer is:
biretta
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">clerical cap</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 biretta that I've seen before include "that covers a Catholic priest" , "Battier (anag.)" , "Roman Catholic priest's cap" , "Cloth cap" , "religious headwear" .)