Republicans have clung to this word like it were their religion when attacking Nancy Pelosi's statements regarding how much, or little, she knew about US torture policies. As if what she knew made a bit of difference.
Prevaricate (v) - A fancy word meaning to lie, more specifically to lie by constantly shifting one's position. From the Latin prae meaning before and varicare meaning to straddle.
Prevaricate is not, however, the fanciest word in the English lexicon meaning liar, liar, pants on fire. That award goes to:
Tergiversate (v) - Means to be evasive. From the Latin tergum (back) and vertere (to turn). Literally, to turn one's back.