certitude

from WordNet (r) 3.0 (2006)

certitude
    n 1: total certainty or greater certainty than circumstances
         warrant [syn: {certitude}, {cocksureness},
         {overconfidence}]

from The Collaborative International Dictionary of English v.0.48

Certitude \Cer"ti*tude\, n. [LL. certitudo, fr. L. certus: cf.
   F. certitude. See {Certain}.]
   Freedom from doubt; assurance; certainty. --J. H. Newman.
   [1913 Webster]