unthinkable

adjective

un·​think·​able ˌən-ˈthiŋ-kə-bəl 

1

: not capable of being grasped by the mind

2

: being contrary to what is reasonable, desirable, or probable : being out of the question

unthinkability

ˌən-ˌthiŋ-kə-ˈbi-lə-tē 

noun

unthinkably

ˌən-ˈthiŋ-kə-blē 

adverb

Synonyms of unthinkable

• incredible
• unlikely
• incredulous
• impossible
• inconceivable
• unimaginable
• unbelievable

Examples of unthinkable in a Sentence

to most people it seemed unthinkable that such a gentle man could be guilty of such awful crimes

Recent Examples on the Web

Shares have tumbled over 60% from their November 2024 highs driven by fundamentals but also marked by an unthinkable shock. —Jay Woods, CNBC, 23 Apr. 2026

Across industries, 40% of HR leaders now cite communication training as their top learning and development priority for 2025, according to Gartner—a number that would have been unthinkable a decade ago. —Nick Lichtenberg, Fortune, 23 Apr. 2026

That opened the door to so many people who five years ago would have been unthinkable. —Josef Adalian, Vulture, 23 Apr. 2026

The early-season free fall reached a new, unthinkable low on Tuesday night. —James O'Connell, New York Daily News, 22 Apr. 2026

Word History

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing unthinkable

• the unthinkable

Rhymes for unthinkable

• thinkable

Kids Definition

unthinkable

adjective

un·​think·​able ˌən-ˈthiŋ-kə-bəl 

ˈən-

: not to be thought of or considered as possible

unthinkable cruelty