1. To fall suddenly to the ground, typically from stumbling or tripping. I took a bit of a tumble walking home last night, hence the bruises.

2. To suffer a sudden fall or decline, as of profits, health, quality, etc. The price of shares in the tech giant took a tumble on Tuesday after it emerged that they had been manipulating sales figures over the last five years. My father has been doing remarkably well in his battle with cancer, but he has taken a tumble in the last few days.