The Collaborative International Dictionary of English v.0.48:
Unmovable \Un*mov"a*ble\, a. Immovable. "Steadfast, unmovable." --1 Cor. xv. 58. Locke. [1913 Webster]WordNet (r) 3.0 (2006):
unmovable adj 1: not able or intended to be moved; "the immovable hills" [syn: immovable, immoveable, stabile, unmovable]