disloyal, untrustworthy, and likely to betray trust or confidence; treacherous behavior involves breaking promises, violating agreements, or engaging in acts that harm others despite having given one’s word or made a commitment.


US English

UK English

Part of speech



faithless, disloyal, traitorous, deceitful, untrustworthy, double-crossing, backstabbing, perfidious, false, disloyal


faithful, loyal, trustworthy, honest, dependable, reliable

Example sentences

  • The treacherous employee stole confidential information and sold it to the competitor.
  • The treacherous road was filled with potholes and dangerous curves, making the journey treacherous.
  • The general warned his troops to be wary of the treacherous enemy, who would stop at nothing to win the battle.


The word “treacherous” is often used to describe individuals or actions that are characterized by a lack of trustworthiness or loyalty. A treacherous person can betray trust in various ways, such as breaking promises, engaging in deceitful behavior, or acting in a manner that causes harm to others despite having given their word or made a commitment. Treacherous actions can also be physical, such as leading someone into danger or engaging in activities that pose a threat to others. The word “treacherous” is often used to describe situations or conditions that are perilous or potentially dangerous, such as a treacherous road or a treacherous sea. The negative connotations associated with the word “treacherous” make it a strong term for describing individuals or actions that are untrustworthy and harmful