de·fec·tion /dɪˈfekʃən/ n. 1. 叛逃；背叛，变节 He provided information to the enemy after his defection. 他叛逃后向敌人提供情报。 numerous defections of the members of the party out of office to the ruling party 在野党党员的大量投向执政党 2. 缺乏；失败；丧失；缺点，缺陷，毛病 He was overcome by a sudden defection of courage. 他突然失去了勇气。 3. 不履行义务；不尽职