In Chinese culture, 意外 (yìwài) taps into a worldview where not everything is under an individual's control. It acknowledges the existence of external forces and unforeseen circumstances. While the Western concept of “accident” is very similar, it's often used specifically to mitigate blame (“It was an accident! I didn't mean to!”). 意外 can do this too, but its core feeling is more about the unforeseeable nature of the event itself. A good comparison is the American cultural emphasis on planning and control. An unexpected event can be seen as a failure of planning. In contrast, 意外 carries a more neutral, philosophical acceptance that life is full of things that are “outside one's intentions.” An unexpected encounter with an old friend might be described as an 意外, which feels closer to “serendipity” or the workings of 缘分 (yuánfèn)—a kind of fate that brings people together. It highlights a cultural readiness to accept and adapt to life's unpredictability, whether for good or bad.
意外 is an extremely common and versatile word used in many situations.
The connotation of 意外 is neutral by default. The context tells you if it's a good or bad thing. `发生意外` is almost always negative, while `意外的礼物 (yìwài de lǐwù)` (an unexpected gift) is positive.