Perfidious

//pɚˈfɪdi.əs// adj

adj ·Moderate ·College level

Definitions

Adjective
  1. 1
    Of, pertaining to, or representing perfidy; disloyal to what should command one's fidelity or allegiance.

    "TRINCULO (speaking about Caliban): By this light, a most perfidious and drunken / monster: when his god's asleep, he'll rob his bottle."

Adjective
  1. 1
    tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans wordnet

Synonyms

All synonyms
treacherousdisloyaltraitorousunfaithfulalienatedambidextrous

Example

More examples

"The most perfidious way of harming a cause consists of defending it deliberately with faulty arguments."

Etymology

From Latin perfidiōsus (“treacherous”), from perfidia.

Related phrases

Perfidious Albion

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.