- Guilty of perfidy; violating good faith or vows; false
to trust or confidence reposed; teacherous; faithless; as, a perfidious
friend. - Involving, or characterized by, perfidy.
Meaning of 'perfidious' (Princeton's WordNet)
1 . perfidious
[ s]
Meaning (1): - tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans