The characters combine literally and effectively: “to speak big words.” This imagery directly points to the meaning of making statements that are larger than reality, hence, to boast or brag.
The negativity surrounding `说大话` is deeply rooted in the traditional Chinese cultural value of 谦虚 (qiānxū) - humility and modesty. In Chinese culture, humility is not a sign of weakness but of wisdom, self-awareness, and respect for others. A person who is truly capable doesn't need to announce it; their actions will speak for themselves. Therefore, someone who frequently `说大话` is seen not just as arrogant, but as immature, unreliable, and lacking in self-cultivation. They risk losing 面子 (miànzi) - “face” or social standing, because their words create an expectation that their actions cannot meet. A useful Western comparison is the phrase “to talk a big game.” Both phrases criticize someone whose words outweigh their abilities. However, `说大话` often carries a stronger implication of untrustworthiness. While a certain level of self-promotion might be acceptable or even encouraged in some Western business contexts (“sell yourself”), it can easily be perceived as `说大话` in a Chinese context, where demonstrating capability through quiet, consistent action is more highly prized.
`说大话` is a common term used across various informal and formal settings, almost always as a criticism.