‘撞大运’ is an informal, vivid idiom meaning to strike it rich or succeed spectacularly through sheer, unexpected luck—not skill, effort, or planning. Literally, ‘撞’ (zhuàng) means ‘to bump into’ or ‘to run into by chance’; ‘大’ (dà) means ‘big’ or ‘great’; and ‘运’ (yùn) means ‘luck’ or ‘fortune’. Together, the phrase evokes the image of accidentally colliding with massive good fortune—as if luck were a physical object you stumbled upon.

This expression carries a tone of surprise, irony, or mild disbelief, often implying the outcome was wildly disproportionate to the action taken. It’s commonly used in spoken Chinese, especially when recounting improbable windfalls—like winning a lottery, landing a dream job without applying, or finding rare antiques at a flea market. While playful and colloquial, it’s not appropriate in formal writing or serious contexts.