implacable

His voice is measured, lucid, and implacable.

Sen, who also handled both the black-and-white cinematography and the editing, has a terrific eye for shot composition and sets a deliberate pace that feels implacable rather than merely slow.

Carlo’s implacable bitterness toward his sister stems in part from his blaming her for their brother’s death.

"Even the implacable Logan Roy would smile in delighted amazement if he could see this," Fiona Mountford of iNews wrote of Snook's stage performance.

They campaigned for a decade against an implacable but ill-prepared bloc of New York’s political and corporate establishment.