Snide lady busted in moral offence (6,3)
I believe the answer is:
deadly sin
'moral offence' is the definition.
'snide lady busted' is the wordplay.
'busted' is an anagram indicator.
'snide'+'lady'='snidelady'
'snidelady' with letters rearranged gives 'DEADLY SIN'.
'in' acts as a link.
(Other definitions for deadly sin that I've seen before include "not good - bad" , "envy for example" , "Eg, lust or pride" , "greed, or lust" , "Greed, perhaps" .)