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perfidious

[per-fid-ee-uhs]
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adjective
  1. deliberately faithless; treacherous; deceitful: a perfidious lover.
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Origin of perfidious

First recorded in 1590–1600, perfidious is from the Latin word perfidiōsus faithless, dishonest. See perfidy, -ous
Related formsper·fid·i·ous·ly, adverbper·fid·i·ous·ness, nounun·per·fid·i·ous, adjectiveun·per·fid·i·ous·ly, adverbun·per·fid·i·ous·ness, noun

Synonyms for perfidious

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Antonyms for perfidious

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for perfidiousness

infidelity, fraud, disloyalty, falseness, disbelief, falsity, dishonesty, treason, betrayal, perfidy, doubt, unfaithfulness, skepticism, treachery, inconstancy

Examples from the Web for perfidiousness

Contemporary Examples of perfidiousness

Historical Examples of perfidiousness


British Dictionary definitions for perfidiousness

perfidious

adjective
  1. guilty, treacherous, or faithless; deceitful
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Derived Formsperfidiously, adverbperfidiousness, 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

Word Origin and History for perfidiousness

perfidious

adj.

1590s, from Latin perfidiosus "treacherous," from perfidia (see perfidy). Related: Perfidiously; perfidiousness.

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Online Etymology Dictionary, © 2010 Douglas Harper