immovable

adjective

1 it's best to lock your bike to something immovable:

fixed, secure, stable, rooted, riveted, moored, anchored, braced, set firm, set fast, fast, firm;

stuck, jammed, stiff, unbudgeable.

▷antonyms mobile.

2 she shook him but he sat immovable:

motionless, unmoving, stationary, still, stock-still, at a standstill, not moving a muscle, rooted to the spot, dead still, statue-like;

transfixed, paralysed, frozen.

▷antonyms moving.

3 she was so immovable in her loyalties:

steadfast, unwavering, unswerving, resolute, determined, adamant, firm, unshakeable, unfailing, dogged, tenacious, stubborn, obdurate, inflexible, unyielding, unbending, uncompromising, unrelenting, inexorable, iron-willed, strong-willed, steely, dead set;

North American rock-ribbed;

informal stiff-necked;

rare indurate.

▷antonyms fickle; unsure.

immovable Oxford Dictionary of English