unappeasable
1. [ adjective ] not to be placated or appeased or moved by entreaty
Synonyms: grim stern relentless inexorable unrelenting unforgiving
Examples:

"grim determination" "grim necessity" "Russia's final hour, it seemed, approached with inexorable certainty" "relentless persecution" "the stern demands of parenthood

Related terms: implacable
Similar spelling:   unfeasible
  unpeaceable
  unopposable
  unpassable
  unfeasibility