Together, 孟子 (Mèngzǐ) literally means “Master Meng.”
Mencius is arguably the second-most influential figure in Chinese history, after Confucius himself. His interpretation of Confucianism became the orthodox and officially endorsed version for most of China's imperial history. His most defining contribution is the theory of innate human goodness (性善论, xìng shàn lùn). To explain this, he used a famous thought experiment: imagine anyone, even a cruel tyrant, suddenly seeing a child about to fall into a well. Mencius argued that their immediate, unthinking reaction would be a feeling of alarm and compassion. This feeling isn't for personal gain or to win favor with the child's parents; it's an instantaneous, natural human response. He called this and other similar feelings the “Four Sprouts” (四端, sì duān):
For Mencius, the goal of life and education is to cultivate these sprouts into fully grown virtues. A useful Western comparison is the philosophical debate on human nature between Jean-Jacques Rousseau and Thomas Hobbes. Mencius is very much in the Rousseau camp, believing that humans are born good and are corrupted by poor environments and bad governance. This contrasts sharply with a later Confucian scholar, Xunzi (荀子), whose views were closer to Hobbes, arguing that human nature is inherently selfish and must be corrected through strict ritual and law.
While you won't use “Mencius” in everyday small talk about the weather, his name and ideas are deeply embedded in Chinese culture and conversation, especially in more formal or educational contexts.