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improbus

Etymology and origin of the Latin word improbus

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Confidence
Established
Formation
Derivation
First attested
Twelve Tables
Ultimate origin
Latin (probus)

Pronunciation

  • IPA (Classical): [ˈɪm.prɔ.bʊs][1]
  • IPA (Ecclesiastical): [ˈim.pro.bus][1]

Forms

improbus (feminine improba, neuter improbum, comparative improbior, superlative improbissimus, adverb improbē); first/second-declension adjective[1] Also spelled inprobus.[2]

Etymology

It is from in- “not” and probus “good, upright”.[2][1] Wiktionary reconstructs Proto-Italic *əmproβwos and compares Oscan ⟨amprufid⟩ “improperly”.[1]

Earliest recorded meaning

The OLD's earliest citation is from the Twelve Tables, of something below standard.[2] Köbler dates them about 450 BC.[3]

Semantic evolution

It meant below standard, of poor quality, as in Plautus' improba merx “bad wares”; morally unsound, rascally, as in Plautus; disloyal, ill-disposed, as in Cicero; shameless, greedy, grasping; of actions immoderate, outrageous; and in Ovid wanton.[2][4] Virgil's labor improbus is relentless toil.[4]

In Ecclesiastical Latin it meant evil, troublesome, wrong, bad.[5] British Medieval Latin used it for inferior and for morally unsound.[6]

Timeline

  • c. 450 BC – the Twelve Tables use it.[2][3]
  • c. 250–184 BC – Plautus uses it.[2][3]
  • 81–43 BC – Cicero uses it of the disloyal.[2][3]

Meanings

Adjective

  1. Below standard, inferior.[2]
  2. Wicked, unprincipled, rascally.[2]
  3. Disloyal.[2]
  4. Shameless, greedy; immoderate, relentless.[2][4]
  5. Wanton.[2]

Word family

  • improbitās
  • improbulus

References

  1. ^ a b c d e Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c d Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  4. ^ a b c Gaffiot, Félix (2016), Dictionnaire latin-français, new ed. by Gérard Gréco et al. (Gaffiot 2016), online ed.
  5. ^ Stelten, Leo F. (1995), Dictionary of Ecclesiastical Latin, Peabody, Mass.: Hendrickson
  6. ^ 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

“Improbus.” Etymologically, 16 Oct. 2026, etymologically.com/la/improbus. Accessed 17 Oct. 2026.

Last edited on . ·