The definition of a perfidy is a deliberate betrayal.
An attempt to overthrow the government of the state or nation to which one owes allegiance, by making war against that government or by giving material support to the enemies of that government. In order to be convicted of treason, a person must confess in open court or there must be testimony to overt acts by two witnesses. See also sedition.
Something false; esp., a lie
Lack of fidelity or loyalty.
Reliance on something in the future; hope:
Find another word for treacherousness. In this page you can discover 14 synonyms, antonyms, idiomatic expressions, and related words for treacherousness, like: perfidy, treachery, treason, disloyalty, faithlessness, false-heartedness, falseness, falsity, infidelity, perfidiousness and traitorousness.