Small close-fitting hat or cap (6)
I believe the answer is:
beanie
I believe this is a double definition.
'small close-fitting hat' is the first definition.
(I've seen this before)
'cap' is the second definition.
(I know that beanie is a type of cap)
(Other definitions for beanie that I've seen before include "Topping" , "cap" , "one on the head" , "Small close-fitting hat" .)