Brush carelessly (4)
I believe the answer is:
daub
'brush carelessly' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for daub that I've seen before include "Plaster; paint crudely" , "Smear; bad painting" , "Coat with plaster" , "coat casually" , "Do graffiti" .)