The Collaborative International Dictionary of English v.0.48:

Insincerity \In`sin*cer"i*ty\, n. [Cf. F. insinc['e]rit['e].]
   The quality of being insincere; lack of sincerity, or of
   being in reality what one appears to be; dissimulation;
   hypocritical; deceitfulness; hollowness; untrustworthiness;
   as, the insincerity of a professed friend; the insincerity of
   professions of regard.
   [1913 Webster]

         What men call policy and knowledge of the world, is
         commonly no other thing than dissimulation and
         insincerity.                             --Blair.
   [1913 Webster]

WordNet (r) 3.0 (2006):

insincerity
    n 1: the quality of not being open or truthful; deceitful or
         hypocritical [syn: insincerity, falseness,
         hollowness] [ant: sincerity]