The jembyeong in "this turned out a complete jembyeong" comes, surprisingly, from the name of a cake you eat. The original word is jeonbyeong (煎餠), a flat round griddle cake of glutinous-rice or wheat flour filled with sweet red-bean paste. But this cake had one weakness: however fine it looked fresh off the griddle, leaving it even a little while would let the cakes stick together and slump, collapsing into a shapeless, unappetizing heap. Watching something fall apart so fast no matter how carefully it was made, people began comparing clumsy work or botched jobs to it — "just like a jeonbyeong." As the pronunciation hardened and dialect crept in, jeonbyeong settled into jembyeong, and today it means "hopelessly bad" all on its own.