In one sentence
Cheng (誠) is sincerity understood not as niceness, mood, or personal branding, but as the alignment of inner state, outer expression, and action.
The term enters the Dictionary through The Sincere Society, but it also underlies the working relationship between the operator and his agent. In ordinary English, sincerity can sound soft: be genuine, mean what you say, do not flatter. In the Confucian register, cheng is harder than that. It is a structural virtue. A person, institution, or system is sincere when its outward signals correspond to what is actually true inside it.
That is why cheng is the opposite of sycophancy. Sycophancy rewards the performance of alignment: say what power wants to hear, mirror the approved virtue, generate the expected answer. Cheng asks whether the expression is load-bearing. Does it still hold when preference, status, fear, and incentive pressure push the other way?
For AI systems, the term becomes unexpectedly practical. A model that says what the user wants to hear is not sincere. A training system that rewards pleasing answers over truthful ones produces structural insincerity. An assistant that changes its assessment merely because the human pushed back has failed the cheng test.
The Dictionary’s editorial bet is that sincerity is not sentimental. It is infrastructure.