Formal headwear (3,3)
I believe the answer is:
top hat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">formal headwear</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for top hat that I've seen before include "Formal headgear of lofty sort" , "Man's headgear worn with formal dress" , "It's seen with tails" , "Old film" , "Head gear" .)