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 idea that Knightsbridge would even be under consideration for the 1¼-mile Classic would have been unthinkable until last month; his first 10 career races were all around one turn at either seven furlongs or a mile. — Jay Posner, Los Angeles Times, 23 Aug. 2026

At the end of last year, with the duo having won eight Grand Slams between them in a row, that data point looked unthinkable. — James Hansen, New York Times, 21 Aug. 2026

For Alexandre Gobillard, production director at the Gobillard & Fils Champagne house, beginning the harvest in mid-August was once almost unthinkable. — ABC News, 20 Aug. 2026

The possible move, unthinkable for legacy studios but in keeping with exits by businesses in other sectors, has only stiffened opposition to the merger in some corners. — Dade Hayes, Deadline, 20 Aug. 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