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

Even a week ago, such a turn of events would have been practically unthinkable. —Patrick Boyland, The Athletic, 22 Jan. 2025

Four years ago, the idea of pardons for Jan. 6 rioters seemed unthinkable to most Republicans. —Rachel Scott, ABC News, 21 Jan. 2025

Windows remains a honeypot for cyber attacks and security vulnerabilities, for half or more of its user base to be off support is simply unthinkable. —Zak Doffman, Forbes, 18 Jan. 2025

Democrats on Capitol Hill are already shifting course, embracing legislation to detain undocumented migrants for minor crimes in a move unthinkable to the party just a few years ago. —Michael Wilner, Miami Herald, 17 Jan. 2025

Word History

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing unthinkable

• the unthinkable

Kids Definition

unthinkable

adjective

un·​think·​able ˌən-ˈthiŋ-kə-bəl 

ˈən-

: not to be thought of or considered as possible

unthinkable cruelty