defection (n.)youdaoicibaDictYouDict[defection 词源字典]
1540s, "action of failing;" 1550s, "action of deserting a party, leader, etc." from Latin defectionem (nominative defectio) "desertion, revolt, failure," noun of action from past participle stem of deficere (see deficient). Originally used often of faith.[defection etymology, defection origin, 英语词源]