noun · a person who follows a religion other than the one considered mainstream or "correct", often used in a derogatory way

中世纪的十字军东征是为了对抗他们眼中的异教徒。

noun · a person who has renounced or abandoned their former religious or political principles

他公开背弃了原本的信仰，被以前的信徒们斥为异教徒。

noun, adverb · a person whose beliefs or opinions are in conflict with the official dogma of a church or establishment

在宗教裁判所看来，任何质疑教义的人都是异教徒。