Hairstyle with tight curls (4)
I believe the answer is:
afro
'hairstyle with tight curls' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for afro that I've seen before include "Big hair?" , "Retro hairdo" , "Hairstyle adopted by the young Michael Jackson" , "Style of haircut" , "Of hair style, tightly curled and bushy" .)