Etymologically

foi

Etymology and origin of the French word foi

Confidence
Established
Formation
Inherited
First attested
c. 1050, Vie de saint Alexis (feit)
Inherited from
Latin fides via Old French
Ultimate origin
Latin (fīdō)
Etymology tree
inherited borrowed derived
Latin fides
French foi
Latin fidelis
English infidel

Pronunciation

Forms

foi f (plural fois)[1] Old French feid (about 1050), feit, fei (12th century); foi from the 12th century.[2][3][4]

Etymology

It is inherited from Old French fei, inherited from Latin fidēs (“trust, confidence; good faith, loyalty; promise”), which in Christian Latin took the sense “faith in God”.[5][2][6][3][7][1] The Latin word belongs with fīdō (“to trust”) and foedus (“treaty”), and Rey and the Petit Robert trace it to the Indo-European root Proto-Indo-European *bʰeydʰ- (“to trust; to persuade”), also seen in English bid and German bitten, Littré compares Ancient Greek πείθω (peíthō, “to persuade”).[2][8][1][9]

Cognate with Italian fede, Occitan fe, Catalan fe, Spanish fe, Portuguese fé and Breton feiz.[8][10]

Earliest recorded meaning

The Vie de saint Alexis (about 1050) has feit for faith in God: Quer feit i ert e justice ed amur “for there was faith there, and justice and love”.[5][11]

Semantic evolution

From the 11th century the word has its two basic values of commitment and belief.[2] In the Chanson de Roland (about 1100) it is a pledge of loyalty, par amor et par feid; in the feudal system foi was the oath of fealty of a vassal, as in foi et hommage (Furetière, 1690).[5][9][2][8] Bone foi “good faith” is in Gace Brulé (1181–86), male foi in Beaumanoir (1283), and faire foi “to be evidence” in 1283; the oath par ma foi (12th century) gave ma foi (late 16th century).[5][2]

The sense “trust in someone's word” is in Chrétien de Troyes (1180–91), with ajouter foi (1541) and digne de foi.[5][2] Calvin (1539) uses la vraye Foy Chrestienne for the doctrine itself, Corneille has article de foi (1632), and Madame de Staël (1817) extends it to any firm conviction.[5] Proverbial phrases include la foi du charbonnier “simple faith” and n'avoir ni foi ni loi (1667, Boileau).[4][1]

Timeline

  • c. 1050 – Feit “faith in God”, Vie de saint Alexis.[5]
  • c. 1100 – A pledge of loyalty, Chanson de Roland.[5]
  • 1181–1186 – Bone foi, Gace Brulé.[5]
  • 1283 – Male foi, faire foi, Beaumanoir.[5][2]
  • 1539 – The Christian doctrine, Calvin.[5]
  • 1632 – Article de foi, Corneille.[5]
  • 1667 – N'avoir ni foi ni loi, Boileau.[4]

Meanings

Noun

  1. faith, religious belief: avoir la foi, perdre la foi, profession de foi.[8][1]
  2. Trust, confidence: avoir foi en quelqu'un, ajouter foi à, to believe, digne de foi, trustworthy.[2][1]
  3. Bonne foi, mauvaise foi: good faith, bad faith: être de bonne foi.[2][1]
  4. (dated) A pledge, word: sur la foi de, on the strength of, faire foi, to be authentic evidence, (feudalism) fealty: foi et hommage.[2][8]
  5. Ma foi: well, indeed: ma foi oui.[8][2]
  6. Sans foi ni loi: without scruples.[1][4]

Word family

  • féal
  • fidèle
  • fiancer
  • confiance
  • perfide
  • Latin fidēs

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 i j k l Rey, Alain, ed. (1992), Dictionnaire historique de la langue française, Paris: Le Robert
  3. ^ a b Rey, Alain, ed. (2005), Le Grand Robert de la langue française, electronic version, Paris: Le Robert
  4. ^ a b c d Guilbert, Louis; Lagane, René; Niobey, Georges, eds. (1971–1978; 1989), Grand Larousse de la langue française, Paris: Larousse
  5. ^ a b c d e f g h i j k l Trésor de la langue française informatisé (2004), ATILF – CNRS & Université de Lorraine, atilf.fr/tlfi; electronic version of Imbs, Paul; Quemada, Bernard, eds. (1971–1994), Trésor de la langue française, Paris: CNRS / Gallimard
  6. ^ Bloch, Oscar; Wartburg, Walther von (1989), Dictionnaire étymologique de la langue française, 8th ed., Paris: Presses universitaires de France
  7. ^ Wartburg, Walther von, et al. (1922–2002), Französisches Etymologisches Wörterbuch, 25 vols., Bonn / Leipzig / Basel: Klopp / Teubner / Zbinden, p. 3, 503a
  8. ^ a b c d e f Rey-Debove, Josette; Rey, Alain, eds. (2007), Le Petit Robert de la langue française, Paris: Le Robert
  9. ^ a b Littré, Émile (1873–1877), Dictionnaire de la langue française, 4 vols. and supplement, Paris: Hachette
  10. ^ Meyer-Lübke, Wilhelm (1935), Romanisches etymologisches Wörterbuch, 3rd ed., Heidelberg: Winter
  11. ^ Quemada, Bernard, ed. (1959–2006), Datations et documents lexicographiques (Base historique du vocabulaire français, BHVF), Paris: Klincksieck / CNRS / Champion; ATILF

Related etymologies

Cite this entry

“Foi.” Etymologically, 18 Oct. 2026, etymologically.com/fr/foi. Accessed 18 Oct. 2026.

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