涨知识：13个让你看不懂的英文习语的起源

A "kangaroo court" means that there has been a fast and unfair legal procedure. It likely comes from during the Gold Rush when American courts would skip procedures for quick sentencing.
“袋鼠法庭”（kangaroo court）指的是美国潦草而不公正的审判程序。这句话有可能来源于淘金热时期，因为那个时期的法庭为了快速判决会省略掉一些程序。

Even though Kangaroos are native to Australia, this phrase dates back to the 19th century Gold Rush in America.
尽管袋鼠是澳大利亚独有的动物，但这句话始见于19世纪美国淘金热时期。

The most likely origin of the phrase, according to researchers, is that people who saw the quick sentencing in American courts during this time likened it to kangaroos hopping or skipping.
研究者称，在淘金热时期，人们在法庭上会经常见到快速潦草的审判，而袋鼠是蹦跳着走路的，因此人们把袋鼠的蹦跳比作法庭省略程序的做法。