tergiversation \tuhr-jiv-uhr-SAY-shuhn\, noun:

1. The act of practicing evasion or of being deliberately ambiguous.
2. The act of abandoning a party or cause.

Tergiversation comes from Latin tergiversatus, past participle of tergiversari, "to turn one's back, to shift," from tergum, "back" + versare, frequentative of vertere, "to turn." The verb form is tergiversate.