You use the term “Kangaroo Court” to discuss a bogus or unauthorized court or legal proceeding that blatantly disregards the recognized standards of justice and carries little to no official standing in the territory where it takes place.
Example in use: “The commissioner has been accused of running a ‘Kangaroo court’ that prioritizes his personal agenda.”
"The term ‘Kangaroo Court’ originated in the United States during the Gold Rush of
the mid-1800s, and many scholars agree that it was first used to discuss cases
involving claim jumping. One 1853 example can be seen in an article by Samuel
Adams Hammett titled A Stray Yankee in
Texas: “By a unanimous vote, Judge G—was elected to the bench and the ‘Mestang’
or ‘Kangaroo Court’ regularly organized.”