treacherous

play

adjective treach·er·ous \ˈtre-chə-rəs, ˈtrech-rəs\

Definition of treacherous

1a : likely to betray trust : unreliable a treacherous memoryb : providing insecure footing or support treacherous quicksandc : marked by hidden dangers, hazards, or perils
2 : characterized by or manifesting treachery : perfidious

treacherously

adverb

treacherousness

noun

See treacherous defined for English-language learners

See treacherous defined for kids

Examples of treacherous in a Sentence

a treacherous act of betrayal
They were not prepared to hike over such treacherous terrain.
The snow made their hike all the more treacherous.
Discussions about money can lead couples into treacherous territory.

Recent Examples of treacherous from the Web

It can only be reached by driving five miles over a treacherous and privately owned dirt road and then hiking into the brush.

— kelly kazek, AL.com, "This ghost town deep in the Alabama woods holds a ghostly legend," 18 July 2017
With the very first scene, the one before the opening credits, the plunge back into the savage, treacherous and very occasionally just world of Westeros was complete.

— steve johnson, chicagotribune.com, "'Game of Thrones' returns with murder and intrigue: a recap," 17 July 2017
Along the way, Veronica navigates the treacherous halls of high school filled with obnoxious 1-percenters, aka the 09ers, and sticky social issues that are still super timely right now.

— fawnia soo hoo, Teen Vogue, "Break the Fashion Rules: These Are the 2000s-Throwback Styles You Need in Your Wardrobe Now," 13 July 2017
Despite his run-in, Hillmann says his love for the chaotic and treacherous spectacle of Pamplona's rampaging bulls hasn't wavered.

— Bloomberg.com, "American Gored At Pamplona Bull Run Promises to Run Again," 8 July 2017
The EPA proposal represents the Trump administration’s first foray into the politically treacherous territory of the Renewable Fuel Standard, a program mandating biofuels in gasoline and diesel fuels that Congress established in 2005.

— jennifer a dlouhy, Bloomberg.com, "U.S. Favors Midwest Corn Farmers in Proposed Biofuels Quotas," 5 July 2017
A few have been captured and killed by Islamic State fighters or drowned on the treacherous Mediterranean crossing.

— chicagotribune.com, "Inside Israel's secret program to get rid of African refugees," 5 July 2017
To get their visas, the girls twice made a treacherous 500 mile journey from their hometown of Herat to the American embassy in Kabul.

— laura beck, Cosmopolitan, "Afghanistan's All-Girl Robotics Team Denied Entry to U.S.," 2 July 2017
But gun-control advocates caution that Republicans are treading in politically treacherous territory.

— lisa marie pane, The Seattle Times, "What’s happened to the pro-gun wish list in Washington?," 26 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'treacherous.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of treacherous

14th century

Synonym Discussion of treacherous

faithless, false, disloyal, traitorous, treacherous, perfidious mean untrue to what should command one's fidelity or allegiance. faithless applies to any failure to keep a promise or pledge or any breach of allegiance or loyalty. faithless allies false stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery. betrayed by false friends disloyal implies a lack of complete faithfulness to a friend, cause, leader, or country. disloyal to their country traitorous implies either actual treason or a serious betrayal of trust. traitorous acts punishable by death treacherous implies readiness to betray trust or confidence. a treacherous adviser perfidious adds to faithless the implication of an incapacity for fidelity or reliability. a perfidious double-crosser

TREACHEROUS Defined for English Language Learners

treacherous

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adjective

Definition of treacherous for English Language Learners

: not able to be trusted : showing that someone cannot be trusted
: very dangerous and difficult to deal with

TREACHEROUS Defined for Kids

treacherous

play

adjective treach·er·ous \ˈtre-chə-rəs\

Definition of treacherous for Students

1 : not safe because of hidden dangers This was a treacherous road at night … — John Reynolds Gardiner, Stone Fox
2 : not trustworthy : guilty of betrayal or likely to betray a treacherous enemy