The concept of 人性 (rénxìng) is central to Chinese philosophy, primarily defined by a great debate between two Confucian scholars: Mencius (孟子 Mèngzǐ) and Xunzi (荀子 Xúnzǐ).
This debate is different from the Western concept of “original sin.” The Chinese discussion is fundamentally secular and social. It's not about humanity's relationship with a divine being but about how to best organize society and govern people. Does a government's role involve nurturing the innate goodness within its people (Mencius), or imposing external order to control their base instincts (Xunzi)? This philosophical tension still subtly influences modern Chinese views on education, law, and morality.
In modern conversation, 人性 is a weighty and often serious term. You won't hear it used as casually as “human nature” might be in English.