Synonyms of unthinkable

unthinkable

adjective

ˌən-ˈthiŋ-kə-bəl 

as in incredible

too extraordinary or improbable to believe

to most people it seemed unthinkable that such a gentle man could be guilty of such awful crimes

Synonyms & Similar Words

• incredible
• unlikely
• incredulous
• impossible
• inconceivable
• unimaginable
• unbelievable
• implausible
• absurd
• ridiculous
• unreasonable
• doubtful
• unconceivable
• questionable
• unconvincing
• full of it
• fantastic
• silly
• dubious
• uncompelling
• debatable
• suspect
• hopeless
• suspicious
• disputable
• shaky
• ludicrous
• fishy
• far-fetched
• untenable
• flimsy
• laughable
• comical
• outlandish
• farcical
• preposterous
• indefensible
• dubitable
• dodgy
• doubtable
• risible
• insupportable

Antonyms & Near Antonyms

• conceivable
• possible
• plausible
• thinkable
• imaginable
• convincing
• credible
• believable
• probable
• likely
• creditable
• reasonable
• supposable
• cogitable
• certain
• indisputable
• sure
• unquestionable
• undeniable
• incontestable
• undoubted
• indubitable
• questionless

Example Sentences

Recent Examples of unthinkable

In the case of massive grid sabotage, AI could compound the chaos and lead to a starvation of city-dwellers unthinkable in modern times. — Simon Sebag Montefiore, The Atlantic, 28 June 2026

Once unthinkable, Iran now knows how to make money by blocking access to the crucial waterway, and despite the treaty talks, is already making plans to do so. — Sun Sentinel Editorial Board, Sun Sentinel, 29 June 2026

But football has repeatedly embraced innovations ​once viewed as unthinkable, from the back-pass rule to VAR and longer stoppage time. — Andrew Greif, NBC news, 3 July 2026

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