(informal) ruin a plan or what is being done; change how things are or are being done, often unexpectedly; ruin or mix up another person's success or plan for success. This phrase comes from the fact that until the nineteenth century roads were generally rough and streets were narrow. For country people, the mere act of getting themselves and their goods to market safely over considerable distances was quite an achievement. One can imagine how annoyed they must have been when the carts containing their precious produce were toppled over, particularly if they had perishable items such a s apples, which would become damaged when scattered and ruin the hopes of a profitable sale. —PDC Volume 5 Approved Glossary