unassailable

unassailable — adjective

1. So far ahead in a race, competition, or argument that no one else can possibly b

1.adjectiveC1
Definition

So far ahead in a race, competition, or argument that no one else can possibly beat you or take your position away.

Example

Aoi's team scored fifty points in the first half, giving them an unassailable lead.

collocation: unassailable lead

After the votes were counted, Joaquín's majority in the election was unassailable.

Common collocations
  • unassailable lead
  • unassailable position
  • unassailable advantage
Synonyms
  • unbeatable

    more common in everyday sports contexts

  • invincible

    stronger, often suggests total invincibility in battle or competition

  • dominant

    broader, can describe a general state of control without the 'cannot be defeated' emphasis

Antonyms
  • vulnerable

    the opposite — open to attack or defeat

  • insecure

    suggests a weak or unstable position

Grammar Patterns

unassailable + noun

be/seem + unassailable

Usage Note

Often used with nouns like 'lead', 'position', or 'advantage' to describe a commanding situation in sports, politics, business, or debate.

Common Mistakes

My exam score was unassailable.
My position at the top of my class was unassailable.
unassailable describes a position of strength, not a single score or grade.

2. If a piece of evidence, an argument, or a fact is unassailable, it is so clearly

2.adjectiveC1
Definition

If a piece of evidence, an argument, or a fact is unassailable, it is so clearly true and so firmly supported that no one can reasonably doubt it or argue against it.

Example

The DNA evidence provided unassailable proof that the suspect was at the crime scene.

collocation: unassailable proof

Layla's logic was so clear and well-supported that her conclusion was unassailable.

Common collocations
  • unassailable evidence
  • unassailable proof
  • unassailable argument
  • unassailable facts
Synonyms
  • indisputable

    very similar, perhaps slightly more common in everyday use

  • irrefutable

    stronger emphasis on the impossibility of refuting

  • unquestionable

    focuses on the absence of doubt rather than the strength of evidence

Antonyms

Grammar Patterns

unassailable + noun

be + unassailable

Usage Note

Commonly paired with nouns related to reasoning and proof: 'evidence', 'proof', 'argument', 'logic', 'facts'. This sense applies only to claims or information, not to people or positions.

Common Mistakes

Her opinion about ice cream flavours is unassailable.
Her argument about the safety of the medicine was unassailable.
unassailable requires well-supported evidence, not personal taste.

3. Built or placed in such a way that no enemy can successfully attack it.

3.adjectiveC1
Definition

Built or placed in such a way that no enemy can successfully attack it.

Example

The castle was built on a steep hill with high walls, making it unassailable.

pattern: making + object + unassailable

The mountain fortress was considered unassailable until modern aircraft were developed.

collocation: unassailable fortress

Common collocations
  • unassailable fortress
  • unassailable castle
  • unassailable position
  • unassailable defenses
Synonyms
  • impregnable

    nearly identical, slightly more common for physical fortresses

  • invulnerable

    broader — can refer to people or systems, not just structures

  • secure

    weaker and more general; does not carry the 'impossible to attack' emphasis

Antonyms

Grammar Patterns

unassailable + noun

be + unassailable

unassailable + by + agent

Usage Note

Typically describes physical structures — castles, fortresses, military bases, defensive positions. Figurative use (e.g. 'an unassailable argument') belongs to senses 1 and 2.

Common Mistakes

My house has unassailable locks.
The fortress was unassailable against medieval weapons.
using unassailable for everyday home security sounds exaggerated; reserve for serious defensive structures.

Word family

  • unassailably
    adverbC1
  • assail
    verbC1
  • assailable
    adjectiveC2
  • assailant
    nounC1

Synonym discussion

Sense: adjective/1

All four words describe a position of great strength, but with different emphases. 'Unbeatable' is the most versatile and informal — it fits sports, games, and everyday competition ('an unbeatable offer'). 'Invincible' is more dramatic, suggesting total invincibility in battle or conflict and can sound mythic ('a seemingly invincible army'). 'Dominant' is the broadest, describing a general state of control without the specific suggestion that defeat is impossible ('a dominant market share'). 'Impregnable' originally referred to physical fortresses but is now also used figuratively for arguments or positions that cannot be broken through. 'Unassailable' sits between them: it is more formal than 'unbeatable', less mythic than 'invincible', and more precise than 'dominant'. For example, 'The team built an unassailable lead in the first half' focuses on the impossibility of being caught, while 'The team had a dominant first half' only states they played better.

unbeatableinvincibledominant ↗impregnable

Common collocations

Adverbs

  • virtually unassailable
  • seemingly unassailable
  • politically unassailable
  • almost unassailable

Phrases

  • an unassailable position in
  • an unassailable lead over
  • hold an unassailable

Etymology

LatinOld FrenchEnglish

Formed in English by adding the negative prefix 'un-' to 'assailable', which came from Old French 'assaillir' (to attack). 'Assaillir' traces back to Latin 'assalire', a combination of 'ad-' (toward) and 'salire' (to leap). The literal meaning is 'not able to be leapt upon' — that is, not open to attack. The word is first recorded in English in the mid-16th century, initially describing fortresses and later extended to arguments, positions, and reputations.