Hairdo for a model (4)
I believe the answer is:
afro
'hairdo' is the definition.
(afro is a kind of hairdo)
'for a model' is the wordplay.
'model' is an anagram indicator.
'for'+'a'='fora'
'fora' anagrammed gives 'AFRO'.
(Other definitions for afro that I've seen before include "Of hair style, tightly curled and bushy" , "Bushy hairstyle" , "Big hair?" , "Big hairstyle" , "Retro hairdo" .)