Immobility, n.
Etymology: [L. immobilitas, fr. immobilis immovable; pref. im- not + mobilis movable: cf. F. immobilité. See Mobile.]
The condition or quality of being immobile; fixedness in place or state.
Shades of meaning
Fernald has no entry of its own for immobility; he lists it under apathy.
Where he writes about it:
We speak of insensibility of heart, immobility of countenance. — from apathy