'亏待' (kuī dài) is a verb meaning 'to treat unfairly', 'to neglect', or 'to fail to give proper care, respect, or due consideration'. Literally, 亏 (kuī) means 'loss', 'shortfall', or 'to harm', and 待 (dài) means 'to treat' or 'to deal with'. Together, they convey the idea of treating someone in a way that causes them a moral or emotional 'loss' — not meeting expectations of fairness, kindness, or responsibility. It often implies a breach of duty, especially in relationships where care or reciprocity is assumed, such as between family members, employers and employees, or hosts and guests.

The word carries a strong connotation of guilt or regret and is commonly used in spoken and written Chinese to express concern about having failed someone emotionally or ethically. It’s rarely used in neutral or positive contexts; instead, it signals a sense of obligation unmet or care withheld. While it can describe material neglect (e.g., withholding food or wages), its core nuance is relational and moral — emphasizing emotional or social shortcoming rather than mere physical absence.