Etymologically
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infidelitas

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Forms

īnfidēlitās f (genitive īnfidēlitātis); third declension[1]

Etymology

It is from Latin īnfidēlis (“unfaithful”) + -tās.[2][1][3] Ancient grammarians described it as formed from the dative singular of the adjective.[3]

Earliest recorded meaning

Köbler dates it from Cicero,[4] who speaks of the faithlessness of friendships and asks quantae īnfidēlitātēs in amīcitiīs, “how much faithlessness there is in friendships”.[5]

Semantic evolution

It means faithlessness or inconstancy;[2][5] the TLL finds it in Cicero, Plancus, Caesar and Hirtius, and Cicero uses the plural.[3] Caesar has someone bear the suspicion of disloyalty.[5]

In Christian Latin it is lack of faith, unbelief.[6][7] Medieval Latin used it for disloyalty, an act of treason, and the breaking of a promise or oath.[6] English took infidelity about 1400 for unbelief, from French or Latin, and in the early 15th century for disloyalty to a person.[8]

Timeline

  • 81–43 BC – Cicero uses it of the faithlessness of friends.[5][4]
  • c. 50 BC – Caesar uses it for a suspicion of disloyalty.[5][4]
  • c. 1400 – English borrows it as infidelity, first for unbelief.[8]

Meanings

Noun

  1. Faithlessness, unfaithfulness, inconstancy.[2][5]
  2. (Ecclesiastical Latin) Lack of faith, unbelief.[6][7]
  3. (Medieval Latin) Disloyalty, breach of faith, treason.[6]
  4. (Medieval Latin) Breach of a promise or oath.[6]
  • English infidelity

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
  4. ^ a b c Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  5. ^ a b c d e f Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  6. ^ a b c d e Niermeyer, J. F. (1976), Mediae Latinitatis Lexicon Minus, Leiden: Brill
  7. ^ a b Stelten, Leo F. (1995), Dictionary of Ecclesiastical Latin, Peabody, Mass.: Hendrickson
  8. ^ a b Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com