Definition from Wiktionary, the free dictionary
invulnerable (not comparable)
- Incapable of being wounded, or of receiving injury; not vulnerable.
- Unanswerable; irrefutable; unable to be damaged by an attack or convinced; as, an invulnerable argument.
Related terms 
incapable of being wounded
- invulnerable in The Century Dictionary, The Century Co., New York, 1911
- invulnerable in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
invulnerable m and f (plural invulnerables)