mod. carelessly and awkwardly built. The lawyer’s case was jerry-built, but the jury bought it anyway.
jerry built
Constructed in a cheap, ramshackle, or otherwise insubstantial fashion. Although the phrase is widely thought to have come from the British World War I slang term for “German,” it well antedates the 20th century. Some possibilities are an old English word for tumble, Jericho (as in Joshua causing the walls to come tumbling down).