implacable

The book contains a warning to the BBC from an unnamed source who says William is an "implacable antagonist" and "has people on the case".

After taking office, Cheney pursued with implacable vigor his vision of sweeping presidential authority—an idea known as the unitary executive.

They call out the industry’s tired shapes, implacable business systems, and unsustainable waste, but in ways that celebrate imagination.

For decades, China’s Communist Party has commissioned a steady flow of World War II books, films and television series to bolster its legitimacy, much of which casts Japan as an implacable villain.

They – and Netanyahu – have been implacably opposed to any role for the Palestinian Authority in Gaza, and any pathway to a Palestinian State.