Refuse hard slog (5)
I believe the answer is:
march
'slog' is the definition.
(thesaurus)
'refuse hard' is the wordplay.
'refuse' becomes 'marc' (discarded material in winemaking).
'hard' becomes 'h'.
'marc'+'h'='MARCH'
(Other definitions for march that I've seen before include "Spring" , "Colonel Bogey, for example" , "Military walk; month" , "Moving demonstration" , "Military walking style" .)