perfidious Meaning, Definition & Usage

  1. adjective satellite tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans
    punic; treacherous.
    • Punic faith
    • the perfidious Judas
    • the fiercest and most treacherous of foes
    • treacherous intrigues

WordNet

Per*fid"i*ous adjective
Etymology
L. perfidious.
Definitions
  1. Guilty of perfidy; violating good faith or vows; false to trust or confidence reposed; teacherous; faithless; as, a perfidious friend. Shak.
  2. Involving, or characterized by, perfidy. "Involved in this perfidious fraud." Milton.

Webster 1913