The Collaborative International Dictionary of English v.0.48:

Vaticinate \Va*tic"i*nate\, v. i. & t. [L. vaticinatus, p. p. of
   vaticinari to prophesy, fr. vaticinus prophetical, fr. vates
   a prophet.]
   To prophesy; to foretell; to practice prediction; to utter
   prophecies.
   [1913 Webster]

WordNet (r) 3.0 (2006):

vaticinate
    v 1: predict or reveal through, or as if through, divine
         inspiration [syn: prophesy, vaticinate]
    2: foretell through or as if through the power of prophecy