Soap for hair (7)
I believe the answer is:
shampoo
'soap for hair' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for shampoo that I've seen before include "Would Mao shop for this cleaner?" , "Hair lotion" , "people get set after it" , "Hair-care product" , "Hair-cleaning product" .)