Hat with a brim curled up on three sides (7)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
tricorn
(Other definitions for tricorn that I've seen before include "headgear" , "Three-cornered, hat perhaps" , "head wear" , "Cocked hat with brim turned up on three sides" , "Type of cocked hat" .)