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

But empathy for them is still unthinkable for many in Israel, with memories raw. — Cara Anna, Los Angeles Times, 7 Oct. 2026

No team had ever made the playoffs after back-to-back 100-loss seasons, so to make it after three in a row was unthinkable, especially after one of their versatile pitchers was sidelined in spring training. — Don Riddell, CNN Money, 6 Oct. 2026

Wildfires encroached on major European cities, a once unthinkable threat. — Justin Worland, Time, 3 Oct. 2026

Howard Zinn achieved a level of fame unthinkable for most historians. — Barbara Spindel, Christian Science Monitor, 1 Oct. 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