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Definition of treacherously

treacherously

/ˈtrɛtʃ.ər.əs.li/
treach · er · ous · ly
Adjective:treacherous
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treacherously Lexical Profile

treacherously Game Scores & Validity

• adverb

1

In a manner characterized by betrayal, deceit, or breach of trust; disloyally or faithlessly.

Example

"The advisor acted treacherously by leaking confidential negotiations to the rival firm."

2

In a manner that presents hidden, unpredictable, or severe physical dangers; precariously or hazardously.

Example

"The mountain pass became treacherously icy after the sudden drop in temperature."

Synonyms
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Antonyms
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• Rhymes for treacherously

• Nearby Words

traybake
trayful
treacherous
treacherously
treacherousness
treachery
treacle

Word Origin & Etymology

Formed from the adjective treacherous plus the adverbial suffix -ly; treacherous derives from Middle English and Old French trecherie ('deceit, trickery'), from trechier ('to cheat').

Usage Trend

Historical frequency of usage in published text.

180019102020
Data source: Google Books Ngram Viewer

Cite this Entry

Wordmom. (2026). Definition of Treacherously. In Wordmom Dictionary. Retrieved Nov 5, 2026, from https://wordmom.com/dictionary/treacherously
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