• synonyms


[im-prob-uh-buh l]
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  1. not probable; unlikely to be true or to happen: Rain is improbable tonight.
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Origin of improbable

From the Latin word improbābilis, dating back to 1590–1600. See im-2, probable
Related formsim·prob·a·bly, adverbim·prob·a·ble·ness, nounsu·per·im·prob·a·ble, adjectivesu·per·im·prob·a·ble·ness, nounsu·per·im·prob·a·bly, adverb
Can be confusedimpossible impracticable impractical improbable


See more synonyms for improbable on Thesaurus.com
questionable, doubtful, implausible.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for improbably

Contemporary Examples

Historical Examples

  • Not improbably, the public may yet be gratified with this collection.

    Other Tales and Sketches

    Nathaniel Hawthorne

  • Still, Eirek's Paradise may not improbably have been Ceylon.


    Benjamin Taylor

  • Trafford, not improbably, ruling some rajah's kingdom in the far East.

  • It will be my duty to write to him in a few days, and not improbably with the same result.

    Luttrell Of Arran

    Charles James Lever

  • There would have been a scene, of course; and she, not improbably, might have told her father.

    Is He Popenjoy?

    Anthony Trollope

British Dictionary definitions for improbably


  1. not likely or probable; doubtful; unlikely
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Derived Formsimprobability or improbableness, nounimprobably, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for improbably



1590s, from assimilated form of in- (1) "not, opposite of" + probable, or else from Latin improbabilis. Related: Improbably.

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Online Etymology Dictionary, © 2010 Douglas Harper