the.com/kangaroo court

means An unofficial or sham tribunal that ignores proper legal procedure and typically delivers a predetermined, unjust verdict.

from American slang from the 1800s, likely tied to frontier and Gold Rush justice — quick, rough trials held far from real courts. The 'kangaroo' almost certainly nods to the idea of verdicts leaping over the normal steps of justice (evidence, deliberation) the way the animal leaps over ground, rather than any literal connection to Australia. The exact coiner and first use are unknown, but the term was well established in American English by the mid-1800s, often describing mock trials of debtors or accused criminals by vigilante groups.