inconsistent

American  

[in-kuhn-sis-tuhnt] / ˌɪn kənˈsɪs tənt /

adjective

1. lacking in harmony between the different parts or elements; self-contradictory.

   an inconsistent story.

   Synonyms:

   incoherent

2. lacking agreement, as one thing with another or two or more things in relation to each other; at variance.

   a summary that is inconsistent with the previously stated facts.

   Synonyms:

   irreconcilable, discrepant

3. not consistent in principles, conduct, etc..

   He's so inconsistent we never know if he'll be kind or cruel.

4. acting at variance with professed principles.

5. Logic. incompatible.

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inconsistent British  

/ ˌɪnkənˈsɪstənt /

adjective

1. lacking in consistency, agreement, or compatibility; at variance

2. containing contradictory elements

3. irregular or fickle in behaviour or mood

4. Also: incompatible. maths (of two or more equations) not having one common set of values of the variables: x + 2 y = 5 and x + 2 y = 6 are inconsistent

5. logic (of a set of propositions) enabling an explicit contradiction to be validly derived

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Synonym Usage

Inconsistent, incompatible, incongruous refer to things that are out of keeping with each other. That which is inconsistent involves variance, discrepancy, or even contradiction, especially from the point of view of truth, reason, or logic: His actions are inconsistent with his statements. Incompatible implies incapability of close association or harmonious relationship, as from differences of nature, character, temperament, and the like: actions incompatible with honesty of purpose; qualities that make two people incompatible. Something that is incongruous is inappropriate or out of keeping, often to the point of being ridiculous or absurd: Incongruous characters or situations frequently provide a basis for comedy.

Other Word Forms

• inconsistently
  adverb

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Etymology

Origin of inconsistent

First recorded in 1640–50; in- ³ + consistent

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Explanation

Inconsistent describes something that's varied or irregular. So if you're supposed to floss every day, but you only remember every now and then, your commitment to oral hygiene could be called inconsistent. The adjective inconsistent first came into use in the 1640’s, with the sense of “not agreeing in substance or form.” Broken down into its roots, in plus consistent, the word literally means "not consistent." Behavior, results in lab experiments, and your cooking skills could all be described as inconsistent if they are irregular, spotty, and hard to predict.

Example Sentences

See Examples For:

inconsistent

Detectives then found a pattern of invoices, often for food items inconsistent with school meals, but matching dishes on the menu of his private catering business Flava 2 You, said Borges.

From Los Angeles Times ● Oct. 30, 2026

The practice of excluding or keeping gains and losses such as these has been inconsistent across the biggest tech companies.

From The Wall Street Journal ● Oct. 27, 2026

His lawyers challenged the claim, citing "several inconsistent versions of the allegations", including a reference to $5 million rather than euros at a Mauritian bail hearing.

From Barron's ● Oct. 23, 2026

For much of that time, the evidence remained uncertain because studies produced inconsistent findings and employed different experimental methods.

From Science Daily ● Oct. 20, 2026

Yet it’s always struck me how inconsistent these various authors have been in their use of large numbers.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos

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Related Words

• conflicting
• contrary
• erratic
• illogical
• incompatible
• irreconcilable
• uncertain
• unpredictable

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