per·fi·dy
noun/ˈpɜːfədi/
/ˈpɜːrfədi/
[uncountable] (literary)- unfair treatment of somebody who trusts you
背叛；背信弃义 - In Act 2 he learns of Giovanni’s perfidy and swears revenge.
在第二幕中，他得知乔瓦尼的背信弃义，并发誓要报仇。
Word Originlate 16th cent.: via French from Latin perfidia, from perfidus ‘treacherous’, based on per- ‘to ill effect’ + fides ‘faith’. - In Act 2 he learns of Giovanni’s perfidy and swears revenge.