TREACHEROUS Synonyms: 65 Similar and Opposite Words

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

treacherous

adjective

ˈtre-chə-rəs

Definition of treacherous

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

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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 Taking the route around the Horn of Africa rather than going through the now-treacherous Bab el-Mandab Strait and on through the Suez Canal adds millions to overall costs. — David Faris, Washington Post, 5 Oct. 2026 The insulation of the mulch will help keep the bulbs dormant during those treacherous warm spells in late winter and early spring. — Beth Botts, Chicago Tribune, 4 Oct. 2026 Hiring has cooled, mortgage rates recently topped 7%, and inflation is still sufficiently elevated to make boasting about the economy treacherous. — Nick Lichtenberg, Fortune, 3 Oct. 2026 Many of these migrants navigate the passage on makeshift boats that can capsize in treacherous waters. — Landon Mion, FOXNews.com, 29 Sep. 2026 See All Example Sentences for treacherous

Recent Examples of Synonyms for treacherous

Adjective

Telemachus’ lone contribution is killing Melanthius, the traitorous Ithacan farmhand, thus preventing him from continuing to arm the suitors.

— Marlow Stern, Variety, 17 July 2026
And at the very center of Hell is Satan himself, the traitorous Archangel Lucifer, depicted as a monstrous creature with wings and three heads.

— Keith Cooper, Space.com, 11 May 2026

Definition of traitorous

Adjective

Even so, officials recommend residents consider backup ways to communicate in case cell service is unreliable.

— Sarah Horbacewicz, CBS News, 15 Oct. 2026
State officials say the federal data are unreliable and the demand comes too close to the election.

— Kevin Rector, Los Angeles Times, 15 Oct. 2026

Definition of unreliable

Adjective

Screening mammograms miss about one in eight breast cancers overall, and people with dense breasts are more likely to get false-negative results, the American Cancer Society reports.

— Samantha Agate, Kansas City Star, 14 Oct. 2026
Overall, screening mammograms miss about one in eight breast cancers, and people with dense breasts are more likely to get false-negative results.

— Samantha Agate, Charlotte Observer, 14 Oct. 2026

Definition of false

Browse Nearby Words

treacheries

treacherous

treacherousness

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“Treacherous.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/treacherous. Accessed 22 Oct. 2026.

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Synonyms of treacherous

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