treacherous
Treacherous (adj) means willing to betray trust; disloyal and deceitful. Example: “His treacherous business partner sold the company's secrets to a rival.”
How to use treacherous
Learner’s notesIn plain EnglishTreacherous describes either a person who betrays trust or a situation/place that's secretly dangerous.
Word forms
more treacherous comparative, most treacherous superlative
Fill the gap
Can you complete this real example?
His _____ business partner sold the company's secrets to a rival.
Etymology
From Old French trecheros, "deceitful" — related to "treachery."
Synonyms
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Related words
Rhymes for treacherous
See all rhymes for treacherous →Frequently asked questions
What does “treacherous” mean?
The word “treacherous” means willing to betray trust; disloyal and deceitful. In plain terms, treacherous describes either a person who betrays trust or a situation/place that's secretly dangerous.
How do you pronounce “treacherous”?
“Treacherous” is pronounced TREHT-shuh-ruhs (/ˈtɹɛt͡ʃəɹəs/ in IPA).
How do you use “treacherous” in a sentence?
Here is “treacherous” used in a sentence: “His treacherous business partner sold the company's secrets to a rival.”
What is another word for “treacherous”?
Words with a similar meaning to “treacherous” include booky, dastardly, disleal, disloyal, double-dealing and double-crossing.
What is the opposite of “treacherous”?
The opposite of “treacherous” — its antonyms — are faithful, fidelitous, leal, loyal and steadfast.
What part of speech is “treacherous”?
“Treacherous” is an adjective.
Where does the word “treacherous” come from?
The word “treacherous” comes from Old French. From Old French trecheros, "deceitful" — related to "treachery.".
Is “treacherous” a common word?
“Treacherous” is an uncommon word in modern English, usually learned at around the C2 level.