The Collaborative International Dictionary of English v.0.48:

Incertitude \In*cer"ti*tude\, n. [Cf. F. incertitude, LL.
   incertitudo, fr. L. incertus. See Incertain.]
   Uncertainty; doubtfulness; doubt.
   [1913 Webster]

         The incertitude and instability of this life.
                                                  --Holland.
   [1913 Webster]

         He fails . . . from mere incertitude or irresolution.
                                                  --I. Taylor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

incertitude
    n 1: the state of being unsure of something [syn: doubt,
         uncertainty, incertitude, dubiety, doubtfulness,
         dubiousness] [ant: certainty]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "incertitude":
   capriciousness, chance, chanciness, changeableness, erraticism,
   erraticness, fickleness, hesitancy, hesitation, incalculability,
   indecision, indecisiveness, indemonstrability, indeterminacy,
   indetermination, indeterminism, irresolution, luck, randomness,
   suspense, suspensefulness, unaccountability, uncertainness,
   uncertainty, uncertainty principle, undecidedness,
   undeterminedness, unforeseeableness, unpredictability,
   unprovability, unsureness, unverifiability, vacillation,
   whimsicality