inconsistent

inconsistent — adjective

1. used to describe a set of ideas, statements, or facts where one part opposes ano

1.adjectiveB2
Definition

used to describe a set of ideas, statements, or facts where one part opposes another part, so that they cannot all be correct at the same time

Example

The witness gave two inconsistent accounts of what happened that night.

inconsistent + accounts / statements / claims

Salma's views on climate change are inconsistent with the company's green policies.

be inconsistent with [something]

Common collocations
  • inconsistent with
  • inconsistent statements
  • inconsistent accounts
  • inconsistent data
  • mutually inconsistent
  • logically inconsistent
  • inconsistent findings
Synonyms
  • contradictory

    stronger than inconsistent; contradictory claims directly deny each other, whereas inconsistent claims simply do not fit together

  • incompatible

    focuses on two things being unable to exist or work together, while inconsistent is about factual or logical disagreement

  • conflicting

    less formal than inconsistent, often used for schedules, interests, or opinions that oppose each other

Antonyms
  • consistent

    the direct opposite; a set of ideas where all parts agree with one another

Grammar Patterns

be inconsistent with [noun phrase]

it is inconsistent to [verb] ... while [verb] ...

Usage Note

Frequently followed by the preposition 'with' to indicate what the subject does not match. The subject is usually an idea, claim, statement, or piece of evidence.

Common Mistakes

This theory is inconsistent to the available evidence.
This theory is inconsistent with the available evidence.
The correct preposition after 'inconsistent' in this sense is always 'with,' never 'to.'

2. changing so often in quality or conduct that the person or thing becomes difficu

2.adjectiveB2
Definition

changing so often in quality or conduct that the person or thing becomes difficult to trust or rely on

Example

The team's inconsistent performance frustrated their coach throughout the season.

inconsistent + performance / quality / results

Hassan has been inconsistent in his attendance this term, missing nearly one class out of three.

be inconsistent in [something]

Common collocations
  • inconsistent performance
  • inconsistent quality
  • inconsistent behaviour
  • inconsistent results
  • inconsistent service
  • inconsistent player
  • inconsistent attendance
Synonyms
  • erratic

    emphasises unpredictable and irregular change, often with a stronger negative tone than inconsistent

  • variable

    more neutral than inconsistent; describes something that naturally changes without implying fault

  • uneven

    specifically describes quality that varies between high and low, especially in work or performance

Antonyms
  • consistent

    describes behaviour or quality that stays steady and dependable over time

  • steady

    emphasises reliability and lack of unwanted change in performance or behaviour

Grammar Patterns

inconsistent + noun (performance / quality / results)

be inconsistent in [gerund / noun phrase]

Usage Note

Often used attributively (before a noun) to describe things whose quality varies from one time to another, such as performance, service, or results. Commonly describes a person's behaviour, work, or skill level.

Common Mistakes

He is an inconsistently player.
He is an inconsistent player.
Before a noun, use the adjective form 'inconsistent,' not the adverb 'inconsistently.'

Word family

Synonym discussion

Sense: adjective/1

Contradictory is the strongest word of this group — if two statements are contradictory, one directly denies the other, leaving no middle ground. Incompatible means two things cannot coexist or work together; it is broader than inconsistent and applies to systems, personalities, or technologies. Conflicting is a less formal alternative, often used for competing interests, schedules, or emotions. Erratic and unreliable belong to sense 2 (erratic describes behaviour that changes unpredictably, while unreliable focuses on the outcome of not being trustworthy). To choose the right word: if you mean 'ideas do not match,' use inconsistent or contradictory depending on strength; if you mean 'performance keeps changing,' use erratic or inconsistent (sense 2). For example, 'His speech contained several contradictory claims' (direct denial) versus 'The quality of her work is inconsistent' (varies from good to bad).

contradictory ↗incompatible ↗conflictingerraticunreliable ↗

Common collocations

Nouns

  • inconsistent results
  • inconsistent data
  • inconsistent behaviour

Adverbs

  • wildly inconsistent
  • fundamentally inconsistent
  • seemingly inconsistent
  • apparently inconsistent
  • totally inconsistent

Phrases

  • inconsistent with each other
  • inconsistent with the evidence
  • inconsistent with the facts

Prepositions

  • inconsistent with

Etymology

LatinFrenchEnglish

Derived from the Latin prefix 'in-' meaning 'not' combined with 'consistentem,' the present participle of 'consistere' meaning 'to stand firm, stop, or stand still.' The word entered English in the 1600s with the sense of 'not agreeing in substance or form.'