Professional misconduct involved clear impact (11)
I believe the answer is:
Here is my best explanation:
'professional misconduct' is the definition.
(I've seen this before)
'involved clear impact' is the subsidiary indication.
'involved' indicates anagramming the letters.
'clearimpact' with letters rearranged gives 'malpractice'.
(Other definitions for malpractice that I've seen before include "Improper professional behaviour", "abuse", "Professional misconduct", "Wrongdoing", "unprofessionalism", "Misconduct" and "Improper conduct".)