背恩忘义

Explanation: Back: betrayal. Their gratitude, to live up to other people. 　　Usage: Joint type; as the predicate attribute; containing derogatory 　　Source: "Jinshu Zhong Yi Chuan order": "Although the back of the believers can not win En Wang Yi _set_ out, and dance festival was no lack of people in suicide at the time." 　　Examples: Credit goes to the owner free to stay for the retainers so, on his wife with me, and this ex wet behind the ears, have not been reported, how can this ~ the matter. (Ming Feng Meng, "Awaken the common saying" Volume XIX) Thesaurus:  Beienqiyi