treacherous

adjective

ˈtre-chə-rəs How to pronounce treacherous (audio)
Definition of treacherousnext
as in traitorous
not true in one's allegiance to someone or something a treacherous "friend," she's been known to turn against people in the blink of an eye

Synonyms & Similar Words

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Antonyms & Near Antonyms

Synonym Chooser

How is the word treacherous different from other adjectives like it?

Some common synonyms of treacherous are disloyal, faithless, false, perfidious, and traitorous. While all these words mean "untrue to what should command one's fidelity or allegiance," treacherous implies readiness to betray trust or confidence.

a treacherous adviser

When can disloyal be used instead of treacherous?

Although the words disloyal and treacherous have much in common, disloyal implies a lack of complete faithfulness to a friend, cause, leader, or country.

disloyal to their country

When could faithless be used to replace treacherous?

While in some cases nearly identical to treacherous, faithless applies to any failure to keep a promise or pledge or any breach of allegiance or loyalty.

faithless allies

Where would false be a reasonable alternative to treacherous?

The words false and treacherous are synonyms, but do differ in nuance. Specifically, false stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery.

betrayed by false friends

How do perfidious and faithless relate to one another, in the sense of treacherous?

Perfidious adds to faithless the implication of an incapacity for fidelity or reliability.

a perfidious double-crosser

When is traitorous a more appropriate choice than treacherous?

The synonyms traitorous and treacherous are sometimes interchangeable, but traitorous implies either actual treason or a serious betrayal of trust.

traitorous acts punishable by death

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of treacherous The pine trees are towering and the fairways are twisting and the bunkers are deep and treacherous. —Alex Zietlow, Charlotte Observer, 15 May 2025 Maybe the seemingly long haul on I-95 made treacherous by traffic congestion creates the Miami-Dade County and Broward County division among its residents. —Michelle F. Solomon, Miami Herald, 13 May 2025 Strong gusts can lead to visibility hazards from blowing dust, downed power lines and treacherous driving conditions. —Anna Skinner, MSNBC Newsweek, 12 May 2025 The high elevation and frequent storms contribute to treacherous travel conditions, including the potential for avalanches. —Jackson Thompson, FOXNews.com, 9 May 2025 See All Example Sentences for treacherous
Recent Examples of Synonyms for treacherous
  1. traitorous
  2. unreliable
  3. false
Adjective
  • Michael Fassbender plays a British intelligence officer tasked with finding who leaked a top-secret software program and betrayed their country, and the list of five potentially traitorous suspects includes his own high-profile wife (Cate Blanchett).
    — Brian Truitt, USA Today, 10 May 2025
  • Smith made out their former collaborators to be ungrateful and traitorous, and the kids weren't given the space to question her command.
    — Zoey Lyttle, People.com, 18 Apr. 2025
Definition of traitorous
Adjective
  • The cooling system in her second-story apartment in Albuquerque, New Mexico, had always been unreliable.
    — Ignacio Calderon, USA Today, 21 May 2025
  • This showed that changes in the truck's speed produced turbulence in the liquid helium, making measurements of its presence unreliable.
    — John Timmer, ArsTechnica, 19 May 2025
Definition of unreliable
Adjective
  • The decision to deploy Dembele as a false nine for a 3-1 home win over Lyon in mid-December proved the spark for a stupendous run of goal-scoring form in which the France international racked up 27 goals in only 22 appearances.
    — Tom Williams, New York Times, 30 May 2025
  • Their accountant filed two false corporate tax returns, claiming one of the couple’s firms earned no money in 2015 and 2016.
    — Howard Gleckman, Forbes.com, 30 May 2025
Definition of false

Browse Nearby Words

treacheries
treacherous
treacherousness
See all Nearby Words

Cite this Entry

“Treacherous.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/treacherous. Accessed 4 Jun. 2025.

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