To roll or fall end-over-end, or to perform acrobatic rolls and flips.
From Middle English 'tumblen,' possibly related to Old High German 'tumelen.' The word may have onomatopoetic origins—it sounds a bit like the rolling action it describes.
The word 'tumble' might actually echo the sound of someone rolling! Onomatopoeia (words that sound like their meaning) is rarer in English than people think, making 'tumble' extra special.
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