This is a fairly vague term. To understand it in the context of advocates’ practice, you need to read and reflect on the case law. It is not only a critical requirement for admission as an advocate – you are required to live up to this standard of conduct in all aspects of your work as an advocate, throughout your career. So you will see the ‘fit and proper’ conduct discussed in various contexts, including admission, striking off the roll, and applications for re-admission after striking off. It also appears where practitioners misbehave in court, eg. by failing to disclose material facts, or actively misleading the court.
The requirement of being ‘fit and proper’ to practice as an advocate is applied in these different contexts, and you will see it being referred to in various different topics in the Ethics curriculum. For example, in the context of overcharging clients (Geach), misleading the court (Swain) and not bringing relevant authorities to the attention of the court during argument (Ulde).
At the heart of the requirement is the characteristic of integrity. This is not merely being an honest person – it requires a proper understanding of our role as advocates, and the standard of conduct required in different situations.