Etymologically

indefessus

Etymology and origin of the Latin word indefessus

Confidence
Established
Formation
Derivation
First attested
70–19 BC, Virgil
Ultimate origin
Latin dēfetīscor
Etymology tree
inherited borrowed derived
Latin defetiscor
Latin defessus
Latin indefessus

Pronunciation

  • Classical: [ɪn.deːˈfɛs.sʊs][1]
  • Ecclesiastical: [in.deˈfɛs.sus][1]

Forms

indēfessus (feminine indēfessa, neuter indēfessum, adverb indēfessē or indēfessim); first/second-declension adjective[1]

Etymology

It is from Latin in- (“not”) + dēfessus (“worn out”).[2][1][3] The participle dēfessus belongs to dēfetīscor (“to grow weary”),[2] which Köbler traces to dē- and fatīscor.[4]

Earliest recorded meaning

Virgil is the first to use it, in the Aeneid, of a tireless right hand.[5][6][4]

Semantic evolution

It is a word of poetry and post-Augustan prose.[5] Ovid sets it against its opposite: Jupiter's wife is dēfessa iubendō, tired of giving orders, while the speaker is indēfessus agendō, tireless in carrying them out.[7][6] Tacitus pairs it with assiduus, diligent,[5] and Apuleius has unceasing grief, indēfessus lūctus.[6] Late writers made the adverbs indēfessē and indēfessim, unweariedly.[5]

In the Middle Ages it was used of tireless servants of Christ and soldiers of God, and of unceasing zeal, care or prayer;[8][9] Bede writes of tireless perseverance.[9] It could also mean everlasting or indissoluble.[8]

Timeline

  • 70–19 BC – Virgil uses it of a tireless hand.[5][4]
  • 43 BC–18 AD – Ovid contrasts indēfessus with dēfessa.[7][4]
  • 98–115 AD – Tacitus pairs it with assiduus.[5][4]
  • c. 125–175 AD – Apuleius uses it of unceasing grief.[6][4]
  • 639–709 AD – Aldhelm calls virginity a tireless companion.[9][4]

Meanings

Adjective

  1. Tireless, unwearied, indefatigable.[2][5]
  2. Unceasing, continual.[6]
  3. (Medieval Latin) Everlasting, indissoluble.[8]

References

  1. ^ a b c d 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. ^ Bianchi, Rossella; Lelli, Olga (2014), VOLI: Vocabolario di latino, Florence: Le Monnier
  4. ^ a b c d e f g Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  5. ^ a b c d e f g Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  6. ^ a b c d e Conte, Gian Biagio; Pianezzola, Emilio; Ranucci, Giuliano (2010), il Latino: Vocabolario della lingua latina, 3rd ed., Florence: Le Monnier
  7. ^ a b Georges, Karl Ernst (1913–1918), Ausführliches lateinisch-deutsches Handwörterbuch, 8th ed., ed. Heinrich Georges, Hannover; Leipzig: Hahn
  8. ^ a b c Mittellateinisches Wörterbuch bis zum ausgehenden 13. Jahrhundert (1967–), Munich: C. H. Beck; Bayerische Akademie der Wissenschaften
  9. ^ a b c Latham, R. E., D. R. Howlett, R. K. Ashdowne, et al. (1975–2013), Dictionary of Medieval Latin from British Sources, London: British Academy / Oxford University Press
Cite this entry

“Indefessus.” Etymologically, 20 Oct. 2026, etymologically.com/la/indefessus. Accessed 23 Oct. 2026.

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