Island fellow with headgear of yellowish-brown colour (9)
I believe the answer is:
manhattan
'island' is the definition.
(I've seen this before)
'fellow with headgear of yellowish-brown colour' is the wordplay.
'fellow with' becomes 'man' (I've seen this in other clues).
'headgear' becomes 'hat' (hat is a kind of headgear).
'of yellowish-brown colour' becomes 'tan'.
'man'+'hat'+'tan'='MANHATTAN'
(Other definitions for manhattan that I've seen before include "Vermouth and whiskey, with a dash of bitters" , "Island of New York - cocktail" , "area of New York City" , "intoxicating drink" , "It blended with spirit" .)