Butcher has two main meanings:

1. A person whose job is cutting and preparing meat. A butcher works in a butcher shop or the meat department of a grocery store, using sharp knives and special tools to cut large pieces of meat into smaller portions that families can cook. Butchers need to know animal anatomy, understand different cuts of meat, and maintain very sharp, clean tools. Before supermarkets became common, nearly every town had its own butcher shop where people would buy fresh meat. Many still exist today, especially ones that specialize in high-quality or unusual meats.
2. To do something very badly or clumsily, especially when trying to perform a task that requires skill or care. If someone butchers a piano piece during a recital, they play it so poorly that it's almost unrecognizable. A student might butcher the pronunciation of a French phrase, mangling it beyond recognition. When you butcher a joke by forgetting the punchline or telling it in the wrong order, you ruin what made it funny in the first place. The word suggests making such a thorough mess of something that it can be painful to witness.