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

• fantastic
• fantastical
• implausible
• inconceivable
• incredible
• incredulous
• unbelievable
• uncompelling
• unconceivable
• unconvincing
• unimaginable

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

Reggaeton, Afrobeats, and K-pop now reach English-speaking audiences to an extent that was unthinkable when traditional gatekeepers—major labels, drive-time DJs, Rolling Stone—held more sway. —Spencer Kornhaber, The Atlantic, 5 May 2025

Youth visas: unthinkable just a few years ago As the United Kingdom has been part of the European free movement regime before its exit from the EU, there had previously been no need for such a deal with European countries. —Frey Lindsay, Forbes.com, 28 Apr. 2025

Not long ago, this kind of praise would have been unthinkable from him. —Stephania Taladrid, New Yorker, 21 Apr. 2025

But in the Trump era, the journey from unthinkable to reality has been remarkably short. —Peter Baker, New York Times, 6 Apr. 2025

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