Source : Webster's Revised Unabridged Dictionary (1913)

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

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

   Syn: Dullness; numbness; unfeelingness; stupidity; torpor;
        apathy; impassiveness; indifference.

Source : WordNet®

insensibility
     n 1: a lack of sensibility [ant: {sensibility}]
     2: devoid of passion or feeling [syn: {unfeelingness}, {callousness},
         {hardness}]