What does "inexorable" mean?

Inexorable: Not to be persuaded or moved by entreaty or prayer; firm; determined; unyielding; unchangeable; inflexible; relentless; as, an inexorable prince or tyrant; an inexorable judge. "Inexorable equality of laws." Gibbon. "Death's inexorable doom." Dryden. You are more inhuman, more inexorable, O, ten times more than tigers of Hyrcania. Shak.