perfidious

Pronunciation:  US [pərˈfɪdiəs] UK [pə(r)ˈfɪdiəs]
  • adj.Not to be trusted; Betrayal; Cheats
  • WebThe treacherous; Unfaithful; Dishonest
  • If he is perfidious, he must be a thorough-going fraud.
    Source: D. M. Frame