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

• incredible
• incredulous
• unlikely
• impossible
• inconceivable
• unimaginable
• fantastical
• 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

Lychee trees grow here now, unthinkable a decade ago. —Ariel Saramandi, The Dial, 29 July 2025

What followed would have been unthinkable at the time. —Jim Osman, Forbes.com, 27 July 2025

And in a move that would have been unthinkable even a year ago, India just resumed offering tourist visas for Chinese citizens, ending a five-year freeze following deadly clashes in a disputed border area in 2020. —Danish Manzoor Bhat, MSNBC Newsweek, 26 July 2025

Some people had made banners and waved them during the show, and there were circle pits during our songs, which would be unthinkable back home. —Billboard Japan, Billboard, 23 July 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