- The definition of treacherous is someone who is guilty of dishonesty or betrayal, or something that is dangerous or hazardous.
- An example of treacherous is someone you thought was your friend who shares your secrets with everyone.
- An example of treacherous is ground made slippery because of an ice storm.
- characterized by treachery; traitorous; disloyal; perfidious
- giving a false appearance of safety or reliability; untrustworthy or insecure: treacherous rocks
Origin: Middle English trecherous from Old French trecheros
Used by arrangement with John Wiley & Sons, Inc.
- Marked by betrayal of fidelity, confidence, or trust; perfidious. See Synonyms at faithless.
- Not to be relied on; not dependable or trustworthy.
- Marked by unforeseen hazards; dangerous or deceptive: treacherous waters.
- treachˈer·ous·ly adverb
- treachˈer·ous·ness noun