unalterable
unal·te·rable
adjective
1.
2.
3.
remaining the same for indefinitely long times
Origin
From un- + alterable.
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). CMU Pronouncing Dictionary. WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.