Treacherous (adjective)

Dangerous, particularly because of being unpredictable, unreliable, or untrustworthy.

Origin:

The word 'treacherous' is derived from the middle english word 'trecherous' meaning 'false' or 'unfaithful'.

Examples:

1. The treacherous terrain made it difficult and risky for the hikers to reach their destination.
2. The treacherous road conditions caused by the heavy rain and strong winds made it necessary to delay the journey.
3. The treacherous behavior of the traitor was exposed and punished, causing widespread shock and disappointment.
4. The treacherous waters were known to be unpredictable and prone to sudden storms and shipwrecks.
5. The treacherous nature of the criminal made it difficult for the police to catch and bring him to justice.