Etymologically

fidelis

Etymology and origin of the Latin word fidelis

Confidence
Established
Formation
Derivation
First attested
Naevius
Ultimate origin
Proto-Indo-European (*bʰeidʰ-)
Etymology tree
inherited borrowed derived
Latin fides
Latin fidelis
English infidel

Pronunciation

  • IPA (Classical): [fɪˈdeː.lɪs][1]
  • IPA (Ecclesiastical): [fiˈdɛː.lis][1]

Forms

fidēlis (neuter fidēle, comparative fidēlior, superlative fidēlissimus, adverb fidēliter); third-declension two-termination adjective[1]

Etymology

It is from Latin fidēs (“faith, trust”) + -ēlis.[2][1][3] Fidēs is *fiþ-ē- (“trust”), from Proto-Indo-European *bʰidʰ-eh₁- (“faith”), from the root of fīdō “to trust”.[3]

Earliest recorded meaning

It is found from Naevius onwards.[3] Plautus asks “do me this faithful service”.[2]

Semantic evolution

Of persons it meant keeping faith, faithful, loyal, as Cicero's good parent or faithful guardian, and of actions done in good faith, as Cicero's brave and faithful help.[2][4] It also meant trustworthy, reliable, as Plautus' “you can send no one more trustworthy”.[2]

As a noun it meant a trusted follower, from Cicero onwards.[5] In Christian Latin it meant believing, a believer, and in medieval Latin a vassal.[6][5] Romance kept it, as Spanish fiel and Italian fedele.[1]

Timeline

  • c. 235–200 BC – Naevius uses it.[3][5]
  • c. 250–184 BC – Plautus uses it of loyal service and a trusty messenger.[2][5]
  • 81–43 BC – Cicero uses it of friends and as a noun.[4][5]

Meanings

Adjective

  1. Faithful, loyal, devoted.[2][1]
  2. Done in good faith, sincere.[2][4]
  3. Trustworthy, reliable.[2][1]
  4. (Christian Latin) Believing.[6][1]

Noun

  1. A trusted follower, confidant.[1][5]
  2. (Christian Latin) A believer, (Medieval Latin) a vassal.[6][5]

Word family

  • confidelis
  • fidēlitās
  • īnfidēlis
  • perfidēlis

Usage notes

Döderlein says fidus names a natural quality, “trustworthy”, while fidelis names a moral one, “faithful”.[7]

References

  1. ^ a b c d e f g h i Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c d de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
  4. ^ a b c Gaffiot, Félix (2016), Dictionnaire latin-français, new ed. by Gérard Gréco et al. (Gaffiot 2016), online ed.
  5. ^ a b c d e f g Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  6. ^ a b c Niermeyer, J. F. (1976), Mediae Latinitatis Lexicon Minus, Leiden: Brill
  7. ^ Döderlein, Ludwig (1874), Döderlein’s Hand-book of Latin Synonymes, tr. H. H. Arnold, Andover: W. F. Draper

Descendants

Cite this entry

“Fidelis.” Etymologically, 15 Oct. 2026, etymologically.com/la/fidelis. Accessed 15 Oct. 2026.

Last edited on . ·