Perfidy \Per"fi*dy\ (p[~e]r"f[i^]*d[y^]), n.; pl. {Perfidies}
(-d[i^]z). [L. perfidia, fr. L. perfidus faithless; per (cf.
Skr. par[=a] away) + fides faith: cf. F. perfidie. See
{Faith}.]
The act of violating faith or allegiance; violation of a
promise or vow, or of trust reposed; faithlessness;
treachery.
The ambition and perfidy of tyrants. --Macaulay.
His perfidy to this sacred engagement. --DeQuincey.