inconceivable

inconceivable — adjective

1. So extraordinary, extreme, or shocking that the human mind cannot picture it or

1.adjectiveB2
Definition

So extraordinary, extreme, or shocking that the human mind cannot picture it or fully accept it as real.

Example

It was inconceivable to Sumin that anyone could survive such a terrible car crash.

it + be + inconceivable + that-clause

The idea of life without the internet is almost inconceivable for Wren's younger brother.

subject + be + inconceivable + for [person]

Common collocations
  • utterly inconceivable
  • almost inconceivable
  • previously inconceivable
  • inconceivable to [someone]
  • inconceivable that…
Synonyms
  • unimaginable

    More neutral; does not carry the same shock or moral weight — e.g. 'unimaginable wealth' vs 'inconceivable cruelty'.

  • unthinkable

    Stronger implication that the idea is too horrifying or absurd to be entertained — 'unthinkable' often implies a moral or practical impossibility.

  • incredible

    Less formal and broader in use, can mean 'amazing' without implying impossibility — 'an incredible story' might just be surprising, not inconceivable.

Antonyms
  • conceivable

    The direct opposite; something the mind can picture or accept as possible.

  • imaginable

    Close synonym of 'conceivable'; within the bounds of what one can picture.

Grammar Patterns

it + be + inconceivable + that-clause

it + be + inconceivable + to-infinitive

subject + be + inconceivable

Usage Note

Often used with dummy 'it' as subject, followed by a that-clause or wh-clause. Commonly appears in formal writing and serious news reporting about disasters, scientific discoveries, or moral questions.

Common Mistakes

It is inconceivable for me understanding the theory.
It is inconceivable for me to understand the theory.
Use 'to-infinitive', not a gerund after 'inconceivable for [person]'.
I am inconceivable that it rained.
It is inconceivable to me that it rained.
'Inconceivable' describes the situation, not a person's mental state. Use dummy 'it' + 'to [person]'.

2. So extremely unlikely that it almost cannot happen or be true, even if the idea

2.adjectiveC1
Definition

So extremely unlikely that it almost cannot happen or be true, even if the idea is not literally impossible.

Example

It is inconceivable that a company of that size would go bankrupt overnight.

it + be + inconceivable + that-clause (expressing extreme unlikelihood)

For Camille, spending six months abroad without learning any local language was inconceivable.

Common collocations
  • almost inconceivable
  • utterly inconceivable
  • inconceivable that
  • seem inconceivable
  • politically / economically inconceivable
Synonyms
  • unbelievable

    Less formal and more emotional; can mean 'surprising but true' whereas 'inconceivable' strongly implies 'not going to happen.'

  • impossible

    Stronger and more absolute; 'inconceivable' leaves a tiny margin of possibility, while 'impossible' rules it out entirely.

Antonyms
  • likely

    The direct opposite on the probability scale.

  • plausible

    Something that can reasonably be expected or believed.

Grammar Patterns

it + be + inconceivable + that-clause

it + be + inconceivable + for + noun + to-infinitive

subject + seem/appear + inconceivable

Usage Note

Distinguish from sense 1: sense 2 does not suggest that something defies the imagination — only that it is extremely improbable. Use this sense when the focus is on likelihood rather than mental comprehension.

Common Mistakes

It is inconceivable to rain tomorrow.
It is inconceivable that it will rain tomorrow.
When expressing unlikelihood of an event, use a that-clause rather than a to-infinitive directly after 'inconceivable'.

Word family

  • inconceivably
    adverbC1
  • inconceivability
    nounC2
  • conceivable
    adjectiveB2
  • conceivably
    adverbB2
  • conceive
    verbB2

Synonym discussion

Sense: adjective/1

All three words describe something that is hard to believe or accept, but they differ in tone and scope. 'Unimaginable' is the closest neutral equivalent — it says only that the mind cannot form a picture of it, without carrying shock or moral judgment ('unimaginable beauty', 'unimaginable wealth'). 'Unthinkable' goes further: it implies that the idea is too awful, dangerous, or morally wrong to even consider ('It is unthinkable to abandon a child'). 'Incredible' is the broadest and most informal — it can mean 'hard to believe' in a positive sense ('an incredible view') or a negative one, but it never carries the same weight of impossibility as 'inconceivable'. For example: 'The devastation after the earthquake was unimaginable' (neutral, factual). 'It is unthinkable that no one helped the injured' (moral outrage). 'He told an incredible story about climbing Everest' (surprising, possibly true). None of these three would fit where 'inconceivable' stresses that something defies the very structure of what one knows to be possible.

unimaginable ↗unthinkableincredible ↗

Common collocations

Nouns

Adverbs

Phrases

  • for [someone]

Prepositions

Etymology

LatinEnglish

Formed in English in the early 1600s from the prefix 'in-' (not) plus 'conceivable' (capable of being understood or pictured in the mind). 'Conceivable' itself comes from Latin 'concipere' (to take in, grasp), which is also the root of 'conceive' — the original meaning being 'to take into the mind'. So 'inconceivable' literally means 'not able to be taken into the mind'.