Wavy hairstyle (4)
I believe the answer is:
perm
'wavy hairstyle' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for perm that I've seen before include "Wavy hairstyle" , "Russian port; hairstyle" , "locks far from straight?" , "Hair style (abbr)" , "Football pools forecast - wavy hairdo" .)