适可而止

Origin and story

Zhu Xi uses the exact expression in his commentary on the Analects' Xiang Dang chapter. The underlying text describes Confucius's habits and says that he did not eat excessively. Zhu explains this as stopping at an appropriate point, without greed. The four-character wording is therefore from the Song commentary, not from the original Analects sentence itself.

From this small example of self-restraint, the expression applies broadly to ending an activity before it becomes excessive. It does not mean giving up as soon as something becomes difficult. The essential idea is recognizing a fitting limit, whether in a joke, a request, or an enjoyable pastime.