The characters combine straightforwardly: “To be (为) rich (富) [but] not (不) benevolent (仁).” The structure implies a cause-and-effect or a state of being: in the process of becoming rich, or as a state of being rich, one is not a good person.
The concept of 仁 (rén) is the cornerstone of Confucian philosophy, representing the highest virtue of humaneness, compassion, and benevolence. Ancient Chinese philosophy, particularly as articulated by Mencius (孟子), posits that a moral person, especially one in a position of power or wealth, has a duty to be benevolent to others. 为富不仁 is the direct violation of this sacred social contract. It’s not just about being greedy; it's about a fundamental failure of one's moral duty to society. A Western parallel might be the character of Ebenezer Scrooge before his transformation, or the term “robber baron” used for industrialists in the 19th century. However, those are specific characters or historical labels. 为富不仁 is a more general and deeply philosophical moral judgment. While Western cultures often celebrate the “self-made” individual who achieves wealth through sheer ambition, Chinese culture traditionally places a heavier emphasis on the moral character of the wealthy. A person who is 为富不仁 is seen not just as successful and ruthless, but as fundamentally a bad person who has failed at being human.
This idiom is alive and well in modern China, frequently used to criticize perceived social injustices related to wealth.
The connotation is always strongly negative and accusatory. It's a serious insult that questions someone's fundamental character. While it's a classical idiom (chengyu), it's used in both formal writing and informal rants.