The head cleaner (7)
I believe the answer is:
shampoo
This clue might be a double definition.
'the head' is the first definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'cleaner' is the second definition.
(shampoo cleans hair)
Can you help me to learn more?
(Other definitions for shampoo that I've seen before include "My partner may be set" , "Liquid that goes to your head?" , "Washer for locks" , "hair treatment" , "Hair-cleaning product" .)