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

The traditional approach to flooding in Vermont, which is to put the river and the road back in place and hope that the problem doesn’t return, was unthinkable in Plainfield. —John Seabrook, New Yorker, 21 July 2025

Guided by a resolve never to judge anyone else and a firm belief in second chances, legendary Chiefs coach Andy Reid has leaned on family bonds to sustain him through the highs of victory and the lows of unthinkable tragedy. —Blair Kerkhoff, Kansas City Star, 21 July 2025

Somedays, the aged bourbon stays on shelves all day, which would have been unthinkable just two years ago. —Maggie Menderski, The Courier-Journal, 15 July 2025

For Jones, creating an entire new body of work for a gallery show, when a single painting takes her three months, is unthinkable. —Leah Dolan, CNN Money, 14 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