perfidus

Latin

Etymology

From per (“through; along”) +‎ fidēs (“faith; trust”) +‎ -us (adjectival suffix), based on the phrase per fidem dēcipere (“to deceive through faith”).^[1]

Pronunciation

(Classical Latin) IPA^(key): [ˈpɛr.fɪ.dʊs]
(modern Italianate Ecclesiastical) IPA^(key): [ˈpɛr.fi.d̪us]

Adjective

perfidus (feminine perfida, neuter perfidum); first/second-declension adjective

that breaks one's promise; false; faithless; dishonest; disloyal; deceitful
- 29 BCE – 19 BCE, Virgil, Aeneid 4.305–306:
  “Dissimulāre etiam spērāstī, perfide, tantum
  posse nefās, tacitusque meā dēcēdere terrā?”
  “Had you even hoped to be able to hide so great a crime – you faithless [man]! – and to slip away from my land unnoticed?”^{[note 1]}
(by extension) treacherous; unsafe; dangerous
Synonym: īnfīdus

Declension

First/second-declension adjective.

	masculine	feminine	neuter	masculine	feminine	neuter
	singular			plural
nominative	perfidus	perfida	perfidum	perfidī	perfidae	perfida
genitive	perfidī	perfidae	perfidī	perfidōrum	perfidārum	perfidōrum
dative	perfidō	perfidae	perfidō	perfidīs
accusative	perfidum	perfidam	perfidum	perfidōs	perfidās	perfida
ablative	perfidō	perfidā	perfidō	perfidīs
vocative	perfide	perfida	perfidum	perfidī	perfidae	perfida

Antonyms

(sense 1) castus, honestus, pudīcus

Derived terms

Related terms

Descendants

French: perfide
- German: perfide
- English: perfidy
Italian: perfido
Portuguese: pérfido
Spanish: pérfido

Notes

^ Dido had believed that she and Aeneas shared a commitment, and yet he and the Trojans are preparing to leave Carthage. Translators Shadi Bartsch, Robert Fagles, Stanley Lombardo, Sarah Ruden, and David West supply the noun traitor. Frederick Ahl (Oxford, 2007) translates perfide as you perfidious cheat, and footnotes the irony that Ancient Romans reputed the Carthaginians as being perfidious.

References

^ Walde, Alois, Hofmann, Johann Baptist (1938) “fidēs”, in Lateinisches etymologisches Wörterbuch (in German), 3rd edition, volume I, Heidelberg: Carl Winter, page 494