To make a hash of something

Origin

The phrase "make a hash of something" draws its vivid imagery from the culinary world. A "hash" is a dish composed of chopped-up, often leftover, meat, potatoes, and other ingredients, all mixed together and typically fried. While a good hash can be delicious, the act of "hashing" or chopping things up indiscriminately can also result in a jumbled, unappetizing mess. It was this latter sense—of something being chopped up, muddled, and confused into an unrecognisable state—that the idiom adopted. Emerging in the late 19th century, it quickly became a popular way to describe a task that had been performed so incompetently that its original form or purpose was completely ruined, much like a poorly prepared dish where everything is indiscriminately thrown together.