Sailor hat (6)
I believe the answer is:
boater
I believe this clue is a double definition.
'sailor' is the first definition.
(I know that sailor can be written as boater)
'hat' is the second definition.
(I know that boater is a type of hat)
(Other definitions for boater that I've seen before include "Hard flat straw hat, or person on water" , "Stiff hat made of straw" , "sailor, perhaps" , "Flat-topped straw hat" , "one going in the junk?" .)