unbelievable
Americanadjective
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too dubious or improbable to be believed.
an unbelievable excuse.
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so remarkable as to strain credulity; extraordinary.
the unbelievable fury of the storm; an unbelievable athlete.
adjective
Other Word Forms
Etymology
Origin of unbelievable
First recorded in 1540–50; un- 1 + believe ( def. ) + -able ( def. )
Explanation
The word unbelievable describes something that is beyond understanding, like the idea, until the Middle Ages, that the earth might actually be round. Unbelievable refers to something that seems incredible (Did you hear the story about the guy who was rescued after being stranded at sea for 6 months on a sailboat?), but it can also refer to something that's so unlikely, so improbable, that you're probably not going to be convinced by it (Hey, did you hear the story about the guy who was rescued after being stranded at sea for 6 months with only a log to keep him afloat?).
Vocabulary lists containing unbelievable
Wow! Synonyms for "Amazing"
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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.
Lockwood worked with a student this year who had all the stats —valedictorian, great extracurriculars and an unbelievable story.
From MarketWatch • Apr. 28, 2026
“We look to these influencers who are making these unbelievable foods,” Moss says.
From Salon • Apr. 25, 2026
"An unbelievable result. I can only imagine what Nuno Espirito Santo and Roberto de Zerbi are thinking. They are probably watching from behind the sofa thinking, 'we've got it all on now'."
From BBC • Apr. 24, 2026
The first thing that had to go right was an unbelievable stroke of luck on the unluckiest night of Tatum’s life.
From The Wall Street Journal • Apr. 22, 2026
Looking at him from such close range, it strikes me now with certainty that it’s not the first time I’ve laid eyes on this totally unbelievable guy.
From "I'll Give You the Sun" by Jandy Nelson
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
