Legal wrongdoing (4)
I believe the answer is:
tort
'legal wrongdoing' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tort that I've seen before include "Private wrong for which damages may be claimed" , "Wrongful act (in law)" , "Trot after legal wrong liable to damages" , "Private or civil wrong - trot after it" , "Trot to get legal wrong" .)