unassailable
unas·sai·lable
adjective
1.
- “an impregnable fortress”
- “fortifications that made the frontier inviolable”
2.
impossible to assail
3.
without flaws or loopholes
- “an ironclad contract”
- “a watertight alibi”
- “a bulletproof argument”
Origin
From un- + assailable.
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.