kerflooey

An American slang term meaning something has broken down, stopped working, or gone completely wrong — essentially synonymous with 'kaput' or 'on the fritz.' Typically used in a lighthearted, exasperated way when a device, plan, or system suddenly fails. The word has an onomatopoeic, comic quality that softens frustration. It's been in informal American speech since at least the early 20th century and still pops up in casual conversation.