- inappeasable
- adjimplacable, not to be pacified, unpacifiable, unmollifiable, unreconcilable; unforgiving, grudge-holding, vengeful, revengeful; rigid, firm, adamant, unbending, hard, inexorable, relentless; merciless, unmerciful, pitiless, unpitying; uncompas-sionate, uncompassioned, unsympathizing, unsympathetic, hard-hearted, heartless.
A Note on the Style of the synonym finder. 2014.