inconceivable

adjective

in·​con·​ceiv·​able ˌin-kən-ˈsē-və-bəl 

: not conceivable: such as

a

: unbelievable

It's inconceivable they survived the crash.

b

: impossible to comprehend

… a work of inconceivable difficulty and labour …

—Mary W. Shelley

inconceivability

ˌin-kən-ˌsē-və-ˈbi-lə-tē 

noun

inconceivableness

ˌin-kən-ˈsē-və-bəl-nəs 

noun

inconceivably

ˌin-kən-ˈsē-və-blē 

adverb

Synonyms of inconceivable

• incredible
• incredulous
• unlikely
• impossible
• unthinkable
• unimaginable
• unbelievable

Examples of inconceivable in a Sentence

The fire caused an inconceivable amount of damage.

After coming this far, to quit now would be inconceivable.

Recent Examples on the Web

After already undergoing two Tommy John surgeries to repair his UCL, Antone would now need an inconceivable third. — Cal Phillips, Fort Worth Star-Telegram, 13 Aug. 2026

Sometimes, my mind wanders to a question that feels inconceivable. — Ayana Lage, Vogue, 12 Aug. 2026

The Mets were sellers from the cellar of the National League East at this year’s trade deadline, a once-inconceivable turn of events whose inevitability eroded its surprise. — Tim Britton, New York Times, 4 Aug. 2026

This analogy is strangely anticlimactic and almost consoling, but a pedestrian ending comes with the territory in a scrupulously realistic book about the inconceivable. — Gideon Lewis-Kraus, New Yorker, 25 July 2026

Word History

First Known Use

1624, in the meaning defined above

Rhymes for inconceivable

• achievable
• believable
• conceivable
• perceivable
• receivable
• retrievable
• irretrievable
• unbelievable

Kids Definition

inconceivable

adjective

in·​con·​ceiv·​able ˌin-kən-ˈsē-və-bəl 

: impossible to imagine or believe

inconceivably

-blē 

adverb