decrepit
Very old and falling apart from age or neglect.
Decrepit means worn out, weakened, or falling apart from old age or lack of care. When something is decrepit, it's visibly broken down and barely functioning.
A decrepit barn might have a sagging roof, rotting wood, and holes in the walls. A decrepit car sputters and rattles, barely making it down the street. The word usually describes physical things like buildings, vehicles, or furniture, but it can also describe people who have become very weak and frail. You might read about a decrepit old mansion in a mystery story, with crumbling walls and creaking floorboards.
The word carries a sense of sadness or neglect. A building doesn't become decrepit overnight: it happens gradually as weather, time, and lack of maintenance take their toll. When you call something decrepit, you're saying it's reached the point where it barely works anymore and might collapse or break down completely at any moment. If your bicycle is a little rusty, it's old. If the frame is bent, the chain keeps falling off, and the seat wobbles dangerously, then it's decrepit.