The Collaborative International Dictionary of English v.0.48:

Mendacity \Men*dac"i*ty\, n.; pl. Mendacities. [L.
   mendacitas.]
   1. The quality or state of being mendacious; a habit of
      lying. --Macaulay.
      [1913 Webster]

   2. A falsehood; a lie. --Sir T. Browne.
      [1913 Webster]

   Syn: Lying; deceit; untruth; falsehood.
        [1913 Webster]