The Collaborative International Dictionary of English v.0.48:

Insensibility \In*sen`si*bil"i*ty\, n. [Cf. F.
   insensibilit['e].]
   [1913 Webster]
   1. The state or quality of being insensible; lack of
      sensibility; torpor; unconsciousness; as, the
      insensibility produced by a fall, or by opiates.
      [1913 Webster]

   2. Lack of tenderness or susceptibility of emotion or
      passion; dullness; stupidity.

   Syn: Dullness; numbness; unfeelingness; stupidity; torpor;
        apathy; impassiveness; indifference.
        [1913 Webster]

WordNet (r) 3.0 (2006):

insensibility
    n 1: a lack of sensibility [ant: aesthesia, esthesia,
         sensibility]
    2: devoid of passion or feeling; hardheartedness [syn:
       unfeelingness, callousness, callosity, hardness,
       insensibility]