To fall over, or to make something or someone fall over, especially in a sudden or dramatic way.
The origin is uncertain, but it appears in English in the 1500s, possibly as a frequentative form related to 'top'. It may have been formed to imitate the action of something tipping over.
We use 'topple' not just for objects, but also for governments and leaders, as if they’re tall towers that can be knocked down. The word carries a sense of instability—that something looked solid until the moment it suddenly wasn’t.
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