Abandon brush (5)
I believe the answer is:
scrub
I believe this clue is a double definition.
'abandon' is the first definition.
(thesaurus)
'brush' is the second definition.
(scrub brush is a kind of brush)
(Other definitions for scrub that I've seen before include "Rough country area" , "Axe" , "Rub hard - low vegetation" , "Clean with hard brush and soapy water" , "Clean by rubbing really hard" .)