perfidy /PER-fi-dee/ /ˈpə:fɪdi/. noun. A deliberate betrayal of trust or breach of faith, particularly professing friendship to deceive. More commonly seen in its adjective form perfidious (faithless, deceitful, treacherous). From Latin perfidia (falsehood, treachery), from the phrase per fidem decipere (to deceive through trustingness), from per- (forward, through) + fidem (faith).
“Among all nations they excelled in the union of common sense and vision. But also among all nations they were most ready to betray their visions in the name of common sense. Hence their reputation for perfidy.” (Olaf Stapledon)
“…how insensitive, how perfidious it would have been on our part to be sneaking little kisses and holding hands, without being truly in love…” (Stefan Zweig)
“Ellie showed the kind of cold disinterestedness that raised her above the smiling perfidy of the majority of her kind.” (Edith Wharton)
“…Peter was a worse louser and lackey, perpetrated his low perfidity after Judas had betrayed his Master…” (Flann O’Brien)