When combined, the characters literally mean “the common/normal feelings of people.” This direct construction perfectly captures the idiom's meaning: an emotion or action that is standard for any human being in a given situation.
人之常情 is deeply rooted in a culture that values empathy, understanding, and social harmony. It functions as a social lubricant, allowing people to excuse minor emotional transgressions or comfort those who are feeling down without passing judgment. A close Western equivalent is “it's only human.” However, there's a subtle difference. “It's only human” often implies a flaw or weakness (e.g., “He made a mistake, but he's only human.”). In contrast, 人之常情 is less about fallibility and more about the universality and acceptability of an emotional response. It's not just about acknowledging a weakness; it's about validating a feeling as legitimate and shared. For example, if a friend is crying because they miss their family, saying “这是人之常情 (zhè shì rén zhī cháng qíng)” is a way of saying, “Your feelings are completely valid and normal. Anyone in your shoes would feel the same.” It builds a bridge of common understanding and reinforces social bonds.
This idiom is widely used in both spoken and written Chinese, ranging from casual conversations to more formal contexts.
The connotation is almost always empathetic and neutral-to-positive. It is a phrase of acceptance, not condemnation.