unrelenting

英[ʌnrɪ'lentɪŋ] 美[,ʌnrɪ'lɛntɪŋ]

1. not to be placated or appeased or moved by entreaty;

"grim determination"

"grim necessity"

"Russia's final hour, it seemed, approached with inexorable certainty"

"relentless persecution"

"the stern demands of parenthood"

2. never-ceasing;

"the relentless beat of the drums"