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.
Unbelievable as it sounds, Turgidson was based on a real-life war hawk.
From Salon • Mar. 10, 2026
"Unbelievable statues, come and look at them," said the 79-year-old Republican as he admired two new figures adorning the Rose Garden.
From Barron's • Mar. 2, 2026
Unbelievable goal, actually - a contender for goal of the season.
From BBC • May 5, 2025
Unbelievable finish and great to see him off the mark and flying at Palace.
From BBC • Dec. 16, 2024
Olly: it crossed my mind once or twice or fifteen times Madeline: Unbelievable.
From "Everything, Everything" by Nicola Yoon
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.
