Fashion for a hairstyle (4)
I believe the answer is:
afro
'hairstyle' is the definition.
(type of hairstyle)
'fashion for a' is the wordplay.
'fashion' indicates anagramming the letters.
'for'+'a'='fora'
'fora' with letters rearranged gives 'AFRO'.
(Other definitions for afro that I've seen before include "Style of haircut" , "Hairdo of the 1960s and 70s" , "Retro hairdo" , "Big curly hairdo" , "Big hair?" .)