一般人看到陌生的英文成語，都會先查英文定義，但定義有很多，有的容易了解，有的不容易了解，說明較完整的如下:
Throw (someone) under the bus" is an idiomatic phrase in American English meaning to betray a friend or ally for selfish reasons. It is typically used to describe a self-defensive disavowal and severance of a previously-friendly relationship when the relationship becomes controversial or unpopular or inconvenient
許多從事翻譯工作的人，一看到 to betray a friend or ally就判定這句話有「出賣」的意思，以致沒用心檢視以下這段更貼近於實用語境的說明，即 It is typically used to describe a self-defensive disavowal and severance of a previously-friendly relationship.
因為沒注意到重點為「切割」(disavowal and severance)，就不通過腦筋細想，不參考更多語例，直接翻譯為「出賣」：
The prime minister threw the mayor under the bus by telling the media that he never agreed to a budget increase.
首相出賣了市長，告訴媒體他從未同意增加預算。
顯然，很多人不知道在上面的語境中，throw sb under the bus的語意並非如此，下面的例句亦同：
1. He has been accused of throwing fellow Republicans under the bus for his personal agenda. 他被控為了個人政治目的切割共和黨同志。
2. I'm not going to throw my friend under the bus for something he did 25 years ago. (source: online Cambridge Dictionary) 我不會為了朋友25年前所做的事丟包他。
丟包的原文定義為：to sacrifice some other person, usually one who is undeserving or at least vulnerable, to make personal gain.
語例3. He'd throw his mother under the bus if it'd mean he could beat the rap. (source: Urban Dictionary)如果丟包他老媽能幫他脫罪，他會這樣做。
紙上談兵，是就單一定義單一例句而為的翻譯行為，實戰經驗，是從新聞報導檢視英文成語在不同的語境中的實際用法，在這原則下，我們發現 throw sb under the bus (idiom) 的中文語意實為：
1.切割
After Using Her Feinstein Actually Threw Ford Under The Bus.
參議員Feinstein 用完Ford後就切割了她。
2. 誣陷
Jiang has always liked my girlfriend and has always wanted to date her so he saw his chance to get rid of me so he threw me under the bus. He told my girlfriend that he had seen me with another woman.
小江一直喜歡我的女朋友，一直想跟她約會，現在見到有除掉我的機會，就誣陷我，跟我女朋友說他看到我跟其他女人在一起。
3. 丟包
She was critical to a particular phase of the project but when management didn't need her anymore, they just threw her under the bus.她對這項目的某階段很重要，但公司不再需要她時，就丟包了她。
資料來源: 高階英漢翻譯辭典 京文出版
資料來源: 高階英漢翻譯辭典 京文出版
