The Collaborative International Dictionary of English v.0.48:

Verisimilitude \Ver`i*si*mil"i*tude\, n. [L. verisimilitudo: cf.
   OF. verisimilitude. See Verisimilar.]
   The quality or state of being verisimilar; the appearance of
   truth; probability; likelihood.
   [1913 Webster]

         Verisimilitude and opinion are an easy purchase; but
         true knowledge is dear and difficult.    --Glanvill.
   [1913 Webster]

         All that gives verisimilitude to a narrative. --Sir. W.
                                                  Scott.
   [1913 Webster]

WordNet (r) 3.0 (2006):

verisimilitude
    n 1: the appearance of truth; the quality of seeming to be true