IPA: /ˈtʌmbəˌdaʊn/
KK: /ˈtʌmbəˌdaʊn/
Describing a building or structure that is in very poor condition and likely to fall apart.
They found a tumbledown cottage at the edge of the forest.
Tumbledown → It is formed from "tumble" (from Middle English *tumblen*, meaning to fall or roll) and "down" (from Old English *dūn*, meaning down or downward). The word describes something that has fallen down or is in a state of disrepair, often used to refer to a dilapidated structure.
Imagine something that has 'fallen' ('tumble') and is now 'down' — that's why tumbledown refers to something that has fallen into disrepair.
No commonly confused words.