Scour; bush (5)
I believe the answer is:
scrub
I believe this is a double definition.
'scour' is the first definition.
(I know that scour can be written as scrub)
'bush' is the second definition.
(I know that bush can be written as scrub)
(Other definitions for scrub that I've seen before include "Drop" , "Wash vigorously" , "clean-up" , "Scour; cancel" , "Rub hard with a brush" .)