Definition of perfidity in US English:

perfidity

noun

  • Perfidy.

Origin

Early 17th century; earliest use found in Edward Topsell (d. 1625), Church of England clergyman and author. From classical Latin perfidus faithless, treacherous + -ity. Compare post-classical Latin perfiditas.

Pronunciation

perfidity

/pəˈfɪdɪti/