Wordnet 3.0
NOUN (2)
1. 
 having the strength to withstand attack; 
[syn: invulnerability, impregnability]
2.  the property of being invulnerable;  the property of being incapable of being hurt (physically or emotionally); 
The Collaborative International Dictionary of English v.0.48:
Invulnerability \In*vul"ner*a*bil`i*ty\, n. [Cf. F.
   invuln['e]rabilit['e].]
   Quality or state of being invulnerable.
   [1913 Webster]
WordNet (r) 3.0 (2006):
invulnerability
    n 1: having the strength to withstand attack [syn:
         invulnerability, impregnability]
    2: the property of being invulnerable; the property of being
       incapable of being hurt (physically or emotionally) [ant:
       vulnerability]