Reddish hair dye (5)
I believe the answer is:
henna
'reddish hair dye' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for henna that I've seen before include "Shrub used for cosmetic colouring" , "hair colour?" , "Vegetable dye" , "Reddish brown dye used on hair" , "natural colour?" .)