The Collaborative International Dictionary of English v.0.48:

Insularity \In`su*lar"i*ty\, n. [Cf. F. insularit['e].]
   [1913 Webster]
   1. The state or quality of being an island or consisting of
      islands; insulation.
      [1913 Webster]

            The insularity of Britain was first shown by
            Agricola, who sent his fleet round it. --Pinkerton.
      [1913 Webster]

   2. Narrowness or illiberality of opinion; prejudice;
      exclusiveness; as, the insularity of the Chinese or of the
      aristocracy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

insularity
    n 1: the state of being isolated or detached; "the insulation of
         England was preserved by the English Channel" [syn:
         insulation, insularity, insularism, detachment]