Dictionary.com
Thesaurus.com
Synonyms

improbable

American  
[im-prob-uh-buhl] / ɪmˈprɒb ə bəl /

adjective

  1. not probable; unlikely to be true or to happen.

    Rain is improbable tonight.

    Synonyms:
    implausible, doubtful, questionable

improbable British  
/ ɪmˈprɒbəbəl /

adjective

  1. not likely or probable; doubtful; unlikely

"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

Other Word Forms

  • improbability noun
  • improbableness noun
  • improbably adverb
  • superimprobable adjective
  • superimprobableness noun
  • superimprobably adverb

Etymology

Origin of improbable

From the Latin word improbābilis, dating back to 1590–1600. See im- 2, probable

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Okay, that was improbable, seeing as he hadn’t even realized who I was at first, but one could never be too careful when it came to Rachel’s machinations.

From Literature

It was an outcome she had initially thought was “improbable.”

From Barron's

It was an outcome she had initially thought was “improbable.”

From Barron's

Their stumble, though, has stopped them pulling clear of those teams, and all but ended talk of an improbable title challenge.

From BBC

Down by 18 points in the second quarter, the ailing Mavericks had nearly pulled off an improbable comeback.

From Barron's