The Collaborative International Dictionary of English v.0.48:

Tergiversate \Ter"gi*ver*sate\, v. i. [L. tergiversatus, p. p.
   of tergiversari to turn one's back, to shift; tergum back +
   versare, freq. of vertere to turn. See Verse.]
   To shift; to practice evasion; to use subterfuges; to
   shuffle. [R.] --Bailey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tergiversate
    v 1: be deliberately ambiguous or unclear in order to mislead or
         withhold information [syn: beat around the bush,
         equivocate, tergiversate, prevaricate, palter]
    2: abandon one's beliefs or allegiances [syn: apostatize,
       apostatise, tergiversate]