invulnerable (adj.)
- armed
- cloaked
- copyrighted
- covered
- deathless
- defended
- dependable
- fail-safe
- firm
- guaranteed
- guarded
- harmless
- immortal
- impenetrable
- imperishable
- impregnable
- incontestable
- incorruptible
- indelible
- indestructible
- indomitable
- ineradicable
- inexpugnable
- inextinguishable
- insuperable
- invincible
- inviolable
- irresistible
- overpowering
- overwhelming
- patented
- protected
- quenchless
- reliable
- resistless
- riskless
- safe
- sheltered
- shielded
- sound
- stable
- steady
- trustworthy
- unassailable
- unbeatable
- unconquerable
- undestroyable
- undying
- unhazardous
- unquenchable
- unsubduable
- unsurmountable
- unyielding
