immovable

What it means

1. Incapable of being physically moved: fixed.

   Synonyms: static, unmovable, fixed, immobile, immotile, inanimate, inert, lifeless · Antonyms: movable, ambulatory, animate, kinetic, mobile, motile, motive, movable

2. Steadfast in purpose or intention: unalterable, unyielding.

   I pleaded with him not to resign, but he was immovable.

   1994, Nelson Mandela, Long Walk to Freedom: The Autobiography of Nelson Mandela, London: Abacus, published 2010, page 101

   Synonyms: adamant, staunch, adamant, ardent, grim, untiring, bent on, bloody-minded

3. Not capable of being affected or moved in feeling: impassive.

   How much happier is he […]who ent'ring on himself remains immovable, and smiles at the madness of the Dance

   1690, [John] Dryden, “To the Right Honourable Philip Earl of Leycester, &c.”, in Don Sebastian, King of Portugal: […], London: […] Jo. Hindmarsh, […], →OCLC, (please specify the page number)

   Synonyms: dead inside, unmovable, alexithymic, apathistical, clinical, dull, phlegmatic, cold-blooded

In a sentence

I pleaded with him not to resign, but he was immovable.

1994, Nelson Mandela, Long Walk to Freedom: The Autobiography of Nelson Mandela, London: Abacus, published 2010, page 101

Where it comes from

1. Middle Englishimmevable
2. Englishimmovable

From Middle English immevable, immoveable. Equivalent to im- + movable.