背信弃义
书籍：汉英成语词典
更新时间：2018-12-03 22:37:45
出处：按学科分类—语言、文字 中国对外翻译出版公司《汉英成语词典》第276页（294字）
违背诺言，不讲信义，例他本来和我约好一同创业，谁知他暗地里却先与别人合作，真是背信弃义，卑劣之至!
He had originally agreed to help me in setting up an undertaking，but secretly，he was collaborating with another．Really，what an underhanded and unscrupulous man to go back on his words like that!