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Definitions

unbelievable

[uhn-bi-lee-vuh-buhl] / ˌʌn bɪˈli və bəl /
ADJECTIVE
beyond the imagination
Synonyms
STRONGEST
astonishing implausible impossible improbable inconceivable incredible outlandish preposterous too much unimaginable unthinkable
WEAK
beyond belief cockamamie cockeyed doubtful dubious far-fetched fishy flaky flimsy for the birds full of holes harebrained incogitable kooky lamebrained open to doubt past belief phony questionable reaching scatterbrained screwy staggering suspect thick thin unconvincing unsubstantial weak won't hold water won't wash
Antonyms
STRONGEST
believable conceivable credible imaginable likely plausible possible reasonable tenable
WEAK
real

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.

“It’s a lot of knowledge workers doing similar tasks with data, an unbelievable distribution network” that reaches institutional investors around the globe.

From Barron's • Apr. 3, 2026

There’s “tremendous, unbelievable uncertainty. That’s where we head from here,” he said.

From MarketWatch • Mar. 26, 2026

I've been running into superheroes playing unbelievable snooker.

From BBC • Mar. 18, 2026

The Constitution is an unbelievable secular document to build a framework for ordered liberty.”

From The Wall Street Journal • Mar. 13, 2026

They spoke also of unbelievable things—of Lancelot unhorsed, defeated, kneeling after he had been knocked down.

From "The Once and Future King" by T. H. White

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.