impurity

impurity — noun

1. an unwanted material inside a substance, such as a tiny amount of a different su

1.nounB2
Definition

an unwanted material inside a substance, such as a tiny amount of a different substance that reduces quality or makes it unsafe; also the fact of containing such material

Example

Gabriel tested the river water and found impurities from a nearby factory.

verb 'found' + impurities from [source]

The factory's filters remove most impurities before the water is released.

Common collocations
  • remove impurities
  • contain impurities
  • filter impurities
  • impurities in [substance]
  • impurities from [source]
  • harmful impurities
  • tiny impurities
  • trace impurities
Synonyms
  • contaminant

    more specific — implies the material is harmful or makes something unfit for use

  • pollutant

    narrower — specifically for substances that damage the natural environment

  • adulterant

    technical — a substance deliberately added to lower quality, often in food or fuel

Antonyms
  • purity

    the state of being free from unwanted materials

Grammar Patterns

impurity (countable, a specific unwanted substance)

impurity (uncountable, the state of being impure)

Usage Note

Subject is usually a substance (water, metal, fuel, air) or the material being purified. The countable form ('an impurity', 'impurities') refers to specific unwanted particles or substances, while the uncountable form ('impurity') denotes the state or condition.

Common Mistakes

The water has many impurity.
The water has many impurities.
When referring to specific unwanted particles or substances, use the countable plural form.

2. thoughts about sex or sexual acts viewed as sinful or morally unacceptable in a

2.nounC1
Definition

thoughts about sex or sexual acts viewed as sinful or morally unacceptable in a religious context

Example

The old monk prayed daily to keep his thoughts free from impurity.

keep [possessive] thoughts free from + impurity

Benjamin's grandmother taught him that impurity of the heart was worse than breaking any rule.

Common collocations
  • moral impurity
  • spiritual impurity
  • impurity of the heart
  • impurity of the mind
  • cleanse [oneself/community] of impurity
  • free from impurity
Synonyms
  • sin

    broader — covers all wrongdoing, not exclusively sexual thoughts or acts

  • uncleanness

    archaic or biblical register, more intense religious connotation

  • immorality

    broader — refers to any behaviour against moral principles, not only sexual

Antonyms
  • purity

    freedom from moral or sexual wrongdoing, especially in a religious sense

  • virtue

    positive moral quality or behaviour, active goodness rather than mere absence of fault

Grammar Patterns

impurity (uncountable, moral or religious context)

Usage Note

Frequently appears in religious, moral, or spiritual contexts. This sense is almost always uncountable — the plural form 'impurities' in moral contexts is rare and typically indicates a shift back to the physical sense.

Common Mistakes

She confessed all her impurities to the priest.
She confessed her impurity to the priest.
In the moral or religious sense, 'impurity' is uncountable and should not be pluralised.

Word family

Synonym discussion

Sense: noun/1

Impurity is the broadest term — any unwanted material inside a substance. Contaminant adds the idea of harm: something that makes a substance unsafe or unfit to use, like bacteria in drinking water. Pollutant is narrower still, referring specifically to contaminants that damage the natural environment, such as chemicals released into a river. Adulterant is a technical term for something deliberately added to lower quality or cut costs, most often in food or fuel — for example, water mixed into milk or sand into rice. In everyday language, 'impurity' is the most natural choice; 'contaminant' belongs in health and safety settings; 'pollutant' is mostly environmental; and 'adulterant' is limited to quality-control or forensic contexts.

contaminantpollutant ↗adulterant

Common collocations

Phrases

  • remove impurities
  • contain impurities
  • free from impurity
  • filter out impurities

Prepositions

  • impurities in [substance]
  • impurities from [source]
  • impurity of [type/metal/heart]

Etymology

LatinFrenchEnglish

Impurity entered English through Old French 'impurité', which came from Latin 'impuritas'. The Latin word is formed from the prefix 'im-' meaning 'not' and 'purus' meaning 'clean or pure'. The moral and religious meaning — referring to sinful sexual thoughts — appeared in English around the 1300s, while the physical and scientific meaning — an unwanted substance mixed into something — became widely used during the 1600s and 1700s as chemistry and manufacturing developed.