Shading (4)
I believe the answer is:
tint
'shading' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tint that I've seen before include "'Shade, tone (4)'" , "work for coiffeuse?" , "A slighth shade of colour" , "Hair dye" , "Hue, shade" .)