In Chinese culture, sincerity 真诚 (zhēnchéng) is a highly prized virtue. Therefore, being labeled 虚伪 (xūwěi) is a serious social condemnation. It's much stronger than the English “fake” and carries a heavy moral judgment. A key cultural point of comparison is the Western concept of “politeness.” In many Western contexts, certain social pleasantries (e.g., “How are you?” without expecting a real answer, or giving a mild compliment) are considered standard politeness. However, if these actions are perceived as overly elaborate or without a basis in genuine feeling in a Chinese context, they can easily be interpreted as 虚伪. This is because the action is seen as “empty” (虚) and “fake” (伪), possibly performed to manipulate or gain something without real emotional investment. This is often tied to the concept of 面子 (miànzi), or social face, where someone might engage in 虚伪 behavior to preserve their own or someone else's face, but it's a risky social maneuver.
虚伪 is almost always used with a negative connotation. It's a direct and strong criticism.