A more thorough explanation:

Fama publica is a Latin term that means "public repute". It refers to a person's reputation in the community. In the past, a person's fama publica could be used against them in a criminal proceeding.

For example, in the thirteenth century, when a coroner was holding an inquest over the body of a dead person, the fama publica was twice distilled. The representatives of the vills made presentments to a jury of twelve freeholders, which represented the hundred. Then, such of these presentments as the twelve jurors were willing to 'avow', or make their own, were presented by them to the sheriff.

The legal forefathers of our grand jurors were not in the majority of cases supposed to be reporting crimes that they have witnessed, or even to be the originators of the fama publica. They were handing on and 'avowing' as their own a rumour that has been reported to them by others.

In simple terms, fama publica means what people think about you in your community. If you have a good fama publica, people will trust and respect you. But if you have a bad fama publica, people may not trust you and may even accuse you of wrongdoing.