These are not terms to be thrown about lightly.
Professional misconduct is a serious thing.
So is fraud. A solicitor who has done something which might be described as ethically inappropriate has not necessarily committed an act of professional misconduct. It may be misguided, but it is not necessarily disgraceful or dishonourable. There can be a tendency to think that colleagues are or should somehow be impervious to attack. On the other hand a rash and strong allegation of professional misconduct may reflect the opposite by attempting to intimidate another practitioner by the use of a threat.