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treacherous

[trech-er-uh s] /ˈtrɛtʃ ər əs/
adjective
1.
characterized by faithlessness or readiness to betray trust; traitorous.
2.
deceptive, untrustworthy, or unreliable.
3.
unstable or insecure, as footing.
4.
dangerous; hazardous:
a treacherous climb.
Origin
1300-1350
1300-50; Middle English trecherous < Anglo-French, equivalent to trecher deceiver (trech(ier) to deceive + -er -er2) + -ous -ous. Cf. French tricheur trickster
Related forms
treacherously, adverb
treacherousness, noun
untreacherous, adjective
untreacherously, adverb
untreacherousness, noun
Synonyms
1. unfaithful, faithless, treasonous. 2. deceitful.
Antonyms
1. loyal. 2. reliable.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for treacherous
  • Too bad many of the mines are in regions too dangerous or geographically treacherous for companies to set up camp.
  • The conversation about the value of a degree has taken a treacherous turn.
  • Also, those mentors can help weed out the treacherous people to work for.
  • Chaos villains are an especially treacherous breed because of their random words and actions.
  • The trails into and through the valley were spectacularly scenic, but also treacherous.
  • He examined his patriotic endeavors and his treacherous actions too.
  • Scientific research has its own geography, with well-explored continents and treacherous peaks.
  • They are often spiced with illicit videotapes, treacherous testimony by former confederates, and even covert wiretapping.
  • Many will do whatever it takes, often risking their lives by crossing treacherous terrain.
  • Even the final two weeks, with the weather warming into the teens, proved treacherous.
British Dictionary definitions for treacherous

treacherous

/ˈtrɛtʃərəs/
adjective
1.
betraying or likely to betray faith or confidence
2.
unstable, unreliable, or dangerous: treacherous weather, treacherous ground
Derived Forms
treacherously, adverb
treacherousness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for treacherous
adj.

early 14c., from Old French trecheros (12c.), from trecheur, agent noun from trechier "to cheat, trick" (see trick). Figuratively, of things, from c.1600. Related: Treacherously; treacherousness.

Online Etymology Dictionary, © 2010 Douglas Harper
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