Drunkard turning on husband? Rubbish! (4)
I believe the answer is:
tosh
'rubbish' is the definition.
(I've seen this before)
'drunkard turning on husband?' is the wordplay.
'drunkard' becomes 'sot' ('sot' can be a synonym of 'drunkard').
'turning' says the letters should be written backwards.
'on' means one lot of letters go next to another.
'husband?' becomes 'h'.
'sot' in reverse letter order is 'tos'.
'tos'+'h'='TOSH'
(Other definitions for tosh that I've seen before include "13 [TRIPE]" , "[BLAH]" , "Hooey" , "garbage'" , "Pal" .)