Definition of tergiversation:
(n) :
the act of turning one's back; abandoning something or someone;
betrayal; the act of turning from a clear course of action;
equivocation;
fickleness
"1985: They make their outward impudence their mask, as foxes, the better we may not see where they truly tend, nor their true black tergiversation beneath. -- John Fowles, A Maggot"