Bowler — fellow maybe a grade lower (8)
I believe the answer is:
headgear
But I can't explain it at all! Could you help me understand?
(Other definitions for headgear that I've seen before include "bowler, for example" , "which sits on top of mine?" , "crown, say" , "Mortarboard < , especially" , "Hats, bonnets, caps etc" .)