1 to give information about sb/sth to an enemy; to make a secret known （向敌人）提供情报，泄露机密: She betrayed all the members of the group to the secret police. 她将团里全部成员都出卖给了秘密警察。He refused to betray their plans. 他拒绝泄露他们的计划。to betray your country 背叛祖国 ☞Look at the note at traitor. 参看 traitor 的注释。

2 to hurt sb who trusts you, especially by not being loyal or faithful to him/her 出卖；背叛；辜负: If you take the money you'll betray her trust. 如果你拿走那笔钱，你就会辜负她的信任。When parents get divorced the children often feel betrayed. 父母离婚，孩子们往往觉得遭到背弃。

3 to show a feeling or quality that you would like to keep hidden 显露（想要隐藏的感受或特性）: Her steady voice did not betray the emotion she was feeling. 她声音稳定，没有流露出内心的情感。 ➔betrayal /bɪˈtreɪəl ||; bɪˈtreəl/ noun [C,U]