flip-flopper

基本解释

The great flip-flopper does not convince the conservative base.
这位大骑墙派并不能说服保守派基层。
Exposed as an un-Christian flip-flopper and shorn of the momentum that came from seeming inevitability, she will see her voters melt away.
罗塞夫被揭露为一个言行不一的非基督教徒，并且丧失了必然获胜的势头，她的选民将渐渐消失。
Apart from being dull and being Mormon, which still fans suspicions, the famous flip-flopper is also—with the exception of his fellow Mormon, Jon Huntsman—the least authentic conservative in the race.
除了沉闷无聊，以及仍然招来怀疑的摩门教徒身份外，这位著名的骑墙派可能也是这次竞选中（除了另一位摩门教徒洪博培以外）最不正宗的保守派。

Although does that give Republicans an opportunity to paint another Democratic presidential candidate as a flip-flopper?
NPR: Analysis: Congress And The Cost Of Energy
Nobody wants to be labeled a flip-flopper, not even a member of the FOMC.
FORBES: Through the FOMC's Looking Glass: An Orgy of Transparency
Consciously or otherwise, they reinforce Labour's attack on him as Chameleon Dave, the flip-flopper who believes in nothing.
ECONOMIST: Bagehot