/pərˈfɪdiəs/ – adjective
Definition: bội tín, lừa dối, xảo trá.
A more thorough explanation: Perfidious is an adjective that means deceitful, untrustworthy, or treacherous. In a legal context, it can refer to someone who has willfully and intentionally acted in bad faith or betrayed a trust or duty.
Example: The perfidious actions of the defendant, who deliberately misled the plaintiff in order to gain an unfair advantage, were deemed unethical by the court.