Perfidious
“Perfidious”是形容词，指背信弃义、不忠不信的，语气强烈且正式，常用于谴责违背信任、出卖盟友或破坏誓言的行为。
- “He was accused of perfidious conduct toward his former allies.” (他被指控对昔日盟友背信弃义。)
- “The perfidious betrayal shocked the entire kingdom.” (这次背信弃义的背叛震惊了整个王国。)
- “History remembers the general as a perfidious traitor.” (历史将这位将军铭记为不忠的叛徒。)
词根”perfid-”来自拉丁语”perfidia”（背信），由”per-”（违背）与”fides”（信任、忠诚）组成。
“Perfidious”由”perfidy”加形容词后缀”-ous”构成，“-ous”表示”具有……性质的”。
“Perfidious Albion”（背信弃义的英格兰）是历史上法国等国对英国外交的贬称，体现国际关系中信任与背叛的叙事；该词在文学与政治评论中仍偶见。
- 固定搭配: “perfidious ally” (背信弃义的盟友), “perfidious act” (背信弃义的行为)
“per-”（违背）+ “fid”（信任，如 fidelity）+ “-ous” = 违背信任的，即 perfidious。
“The perfidious advisor sold secrets to the enemy while pretending loyalty. His deception was uncovered only after the war ended.” (这名背信弃义的顾问一边假装忠诚，一边向敌人出卖机密。他的欺骗直到战后才被揭露。)