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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 for treacherously
  • Also, precipitation can make the road treacherously slick.
  • Shady areas and bridge surfaces can be treacherously icy even when other sections of roadway are not.
  • Precipitation can make the road treacherously slick, so use caution during inclement weather.
  • Fallen timber impeded their progress across the treacherously steep ridges, while snow and lack of food depleted their strength.
  • Snow is never a problem, but heavy rains during the winter make the narrow winding roads treacherously slippery.
  • After surrendering according to the usages of war he was treacherously killed.
British Dictionary definitions for treacherously

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 treacherously
treacherous
early 14c., from O.Fr. trecheros (12c.), from trecheur, agent noun from trechier "to cheat, trick" (see trick). Figuratively, of things, from c.1600.
Online Etymology Dictionary, © 2010 Douglas Harper
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