perfidious
/pərˈfɪdiəs/
deceitful and untrustworthy; treacherous
perfidious in a sentence
“The perfidious ally betrayed them at the crucial moment.”
Origin of perfidious
Latin perfidiosus from perfidia treachery from per- through + fides faith, meaning breaking faith
Related Words
specious
superficially plausible but actually wrong; misleading in appearance
spurious
not genuine, authentic, or true; false or fake
fallacious
based on a mistaken belief; containing a fallacy
apocryphal
of doubtful authenticity; widely circulated but probably false
chicanery
the use of trickery to achieve a political, financial, or legal purpose
subterfuge
deceit used to achieve one's goal; a stratagem used to deceive