to fail badly, or to fall from a horse or have a bad accident in a vehicle

If outside buyers or suppliers lose faith, a company can come a cropper very quickly. 如果一家公司的外部买家或供应商失去了信心，这家公司就会很快崩溃。

She came an almighty cropper when her back wheels hit an icy patch. 她的后车轮轧上了一块结冰的路面，出了严重的车祸。