improbable

Borrowed from Latin improbābilis.^[1] By surface analysis, im- +‎ probable.

• (General American) IPA^(key): /ɪmˈpɹɑbəbl̩/
• (Received Pronunciation) IPA^(key): /ɪmˈpɹɒbəbl̩/

• Audio (UK):

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• Audio (US):

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• Hyphenation: im‧prob‧a‧ble

improbable (comparative more improbable, superlative most improbable)

1. Not likely to be true.

   It's highly improbable that aliens abducted you.

   • 1598, John Florio, “Improbabile”, in A Worlde of Words, or Most Copious, and Exact Dictionarie in Italian and English, […], London: […] Arnold Hatfield for Edw[ard] Blount, →OCLC, page 171, column 1:

     Improbabile, that cannot be prooued, improbable.

   • 1674, [Richard Allestree], “Of Positiveness”, in The Government of the Tongue. […], Oxford, Oxfordshire: At the Theater, →OCLC, page 197:

     Nay, if he be of a proud humour, […] he will not Bate an Ace of abſolute certainty, but however doubtful or improbable the thing is, coming f[r]om him it muſt go for an indiſputable truth.

   • 1955 December, “Notes and News: An Old Midland Railway Bridge Notice”, in Railway Magazine, page 877:

     It is highly improbable that the drafter of the notice ever visualised the form that heavy vehicles of the future would take, but the comprehensive wording still covers modern types.

2. Not likely to happen.

   Due to the loss of power, it is improbable that we will begin on time.

• probable

• impossible

improbable m or f (masculine and feminine plural improbables)

1. improbable, unlikely

   Antonym: probable

• improbablement

• improbabilitat

• “improbable”, in Diccionari de la llengua catalana [Dictionary of the Catalan Language] (in Catalan), second edition, Institute of Catalan Studies [Catalan: Institut d'Estudis Catalans], April 2007
• “improbable”, in Gran Diccionari de la Llengua Catalana, Grup Enciclopèdia Catalana, 2026
• “improbable” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.
• Alcover, Antoni Maria; Moll, Francesc de Borja (1963), “improbable”, in Diccionari català-valencià-balear (in Catalan)

From im- +‎ probable.

• IPA^(key): /ɛ̃.pʁɔ.babl/

• Audio (Canada (Shawinigan)):

  (file)

improbable (plural improbables)

1. unlikely, improbable (not likely)

   Synonym: peu probable

• “improbable”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012

• improvável (reintegrationist)
• improbábel

improbable m or f (plural improbables)

1. improbable (not likely to happen)

   Antonym: probable

• improbabilidade

• “improbable”, in Dicionario da Real Academia Galega (in Galician), A Coruña: Royal Galician Academy, 2012–2026

• IPA^(key): /impɾoˈbable/ [ĩm.pɾoˈβ̞a.β̞le]
• Rhymes: -able
• Syllabification: im‧pro‧ba‧ble

improbable m or f (masculine and feminine plural improbables)

1. improbable, unlikely

   Antonym: probable

• “improbable”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8.1, Royal Spanish Academy [Spanish: Real Academia Española], 15 December 2025