Treacherous means someone or something that cannot be trusted, or a situation that is secretly very dangerous.

What does “treacherous” mean?

When you ask “what does treacherous mean,” you’re usually talking about two main ideas:

  1. Untrustworthy or betraying
    • Used for people or actions that break trust or loyalty.
    • Examples:
      • “A treacherous friend shared my secrets.”
   * “A treacherous act of betrayal.”
  1. Dangerous, especially in a hidden or unexpected way
    • Used for places, conditions, or situations that seem okay but are actually risky.
    • Examples:
      • “Treacherous roads covered in ice.”
   * “A treacherous mountain path.”

So if someone says, “That path is treacherous,” they mean it’s risky or unsafe; if they say, “He is treacherous,” they mean he’s likely to betray or deceive others.

Quick facts and examples

  • Part of speech: adjective (“a treacherous road,” “a treacherous person”).
  • Similar words (for people): deceitful, disloyal, perfidious, faithless.
  • Similar words (for situations): dangerous, risky, hazardous.
  • Opposite words: loyal, faithful, honest, dependable.

A simple sentence to remember it:

“The treacherous storm made the roads too dangerous to drive on.”

Tiny origin note

The word comes from Old French forms meaning “cheat” or “deceiver,” so it has always carried a sense of betrayal and dishonesty.

TL;DR: “Treacherous” means untrustworthy (likely to betray) or secretly very dangerous.

Information gathered from public forums or data available on the internet and portrayed here.