1. He is a faithless friend.
    他是个不可靠的朋友。

1. 信念：前山羊皮的主场安得森,前平克.弗洛伊德乐队主唱罗杰.沃特斯,前雷蒙斯鼓手马奇.雷蒙,叫床乐队(Yeah Yeah Yeahs),纽约妞人民公敌死亡汽油弹深紫NOFX圣约伊甸桥与亚特兰蒂斯幻想死域无信念(FAITHLESS)大敌等等欧美超级乐队,

1. 背信弃义的;不忠实的;不诚实的
    If you say that someone is faithless, you mean that they are disloyal or dishonest.

    e.g. She decided to divorce her increasingly faithless and unreliable husband.
           她决定与越来越花心、越来越靠不住的丈夫离婚。

1. having the character of, or characteristic of, a traitor

    e.g. the faithless Benedict Arnold
           a lying traitorous insurrectionist

    Synonym: traitorousunfaithfultreasonabletreasonous