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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Amazing
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un-
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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.
"Please establish a national brain cancer lead and give us a chance to fight for our lives because the things that patients are going through out there are unbelievable and so unjust," he said.
From BBC ● Oct. 14, 2026
The niche, sometimes unbelievable drama of this community attracts rubberneckers who’ve never even attempted German short rows or an Italian bind-off in their lives.
From Slate ● Oct. 11, 2026
“It’s unbelievable when we have a private arrangement with you that you would now CC a producer talking about money,” she said.
From The Wall Street Journal ● Oct. 7, 2026
Daniel described the moment they received a phone call inviting them to Windsor Castle as "unbelievable".
From BBC ● Sep. 29, 2026
Thinking it was his premise that the alchemist found unbelievable, he hurried along.
From "Strange the Dreamer" by Laini Taylor
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.
