unassailable
adjective
1. immune to attack; incapable of being tampered with
Similar word(s): invulnerable, impregnable, inviolable, secure, strong, unattackable
2. impossible to assail
Similar word(s): inviolable, untouchable
3. without flaws or loopholes
Similar word(s): incontestable, incontestible, bulletproof, unshakable, watertight
Sentences with unassailable as an adjective:
- She won the debate with her unassailable logic.