In our traditional culture, the importance of names is self-evident. Generally speaking, except for parents, relatives, friends who are very close to each other, and bosses in the workplace, it is impolite to address others by their first names and surnames. This is especially important for the ancients. In ancient officialdom, there were almost no first-name calls between superiors and subordinates or colleagues at the same level. Even the enemy who beat you to death, avoid using the full name directly when insulting each other.
Back to the ancient officialdom, in fact, the mutual address between ancient officials mainly followed a principle, that is, avoiding calling each other by their full names and making good use of each other's ideograms. In the first case, if two people are in the same camp, the superior can use the word of the subordinate to address the superior, while the subordinate generally uses the surname plus "adult" or a specific official name to show respect.
In the second case, if two people have equal status, as long as the relationship is not particularly bad, they will generally use the other person's words or official titles. Another situation is that people who belong to two opposing camps, no matter who has a higher official position, usually call each other's adults or match their official positions when they meet.