Learn That Word

Synonyms for Inexorable (same or very similar meaning)

WordNet sense 1 (not to be placated or appeased or moved by entreaty):
grim, relentless, stern, unforgiving, unrelenting, unappeasable

WordNet sense 2 (incapable of being placated):
implacable

WordNet sense 3 (impervious to pleas, persuasion, requests, reason):
adamant, adamantine, intransigent

WordNet sense 4 (incapable of change):
inflexible


From the ODE community, based on WordNetadd/edit