Inexorable: Relentless; unalterable. Not persuaded or moved by entreaty or prayer; too firm and determined in purpose to yield; will not bend.

Inexorable comes from the Latin prefix ‘in’ meaning ‘not’ and ‘exorabilis’ meaning ‘easily entreated, or influenced by prayer.’

Exorabilis itself derives from ex (out of) and orare (to pray).

Here are some inexorable synonyms: inflexible, steadfast, steady, sure, uncompromising.

As the inexorable Tom Petty put it in one of my favorite songs, “No, I won’t back down. I’ll stand my ground.”