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

The budget hole for the coming year well exceeds $1 billion, topping last year’s shortfall, which brought the mayor and the City Council to the brink of an unprecedented (and unthinkable) government shutdown. — The Editorial Board, Chicago Tribune, 25 June 2026

Messi already has five, and someone reaching 10 doesn’t seem that unthinkable given the numbers the top players have put up so far. — Dan Santaromita, New York Times, 24 June 2026

There is also the once-unthinkable idea that Marathon could slowly shift its genre. — Paul Tassi, Forbes.com, 23 June 2026

The idea of willingly spending some indeterminate amount of time feeling bad is unthinkable. — Amanda Petrusich, New Yorker, 22 June 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