adjective
immovable
ih-MOO-vuh-bul/ɪˈmuːvəbl/
Fixed so firmly that it cannot be shifted.
The massive boulder remains immovable despite the person's efforts to push it.

Etymology
Negating movable gives the image of something too firmly fixed to shift. The same image applies figuratively to something that cannot be changed.
In context
We are locked in to a crane erection date which is immovable. A huge amount of money has been paid
More examples
- An immovable boulder blocks the narrow trail.
- The rusted bolt seems immovable, even with a wrench.
- Once bolted to the floor, the safe is practically immovable.
Forms
immovable
immovability noun — The state of being impossible to move.
Similar words
- fixed
- Describes something securely attached, without necessarily making movement impossible.
- stationary
- Describes something not moving, rather than impossible to move.