Definition of "Sisyphean"

Four bucketsful of water—one for each cell—seven for the long passage, two for lavatory and w.c.'s, brasses to clean, paint to dust. It seemed a Sisyphean task, no sooner ended than a new one was exacted.

1906, Mary Higgs, Glimpses into the Abyss‎

As the world's drug habit shows, governments are failing in their quest to monitor every London window-box and Andean hillside for banned plants. But even that Sisyphean task looks easy next to the fight against synthetic drugs. No sooner has a drug been blacklisted than chemists adjust their recipe and start churning out a subtly different one.

2013 August 10, “A new prescription”, in The Economist‎, volume 408, number 8848

But whoever does the policing, whether a supervisor or an operator, faces a Sisyphean battle against a well-documented phenomenon: something called automation complacency. When you automate any part of a task, the human overseer starts to trust that the machine has it handled and stops paying attention.

2022 March 8, Lauren Smiley, “‘I’m the Operator’: The Aftermath of a Self-Driving Tragedy”, in Wired‎