adverse

adverse — adjective

1. bringing bad results, or making it harder for a person, plan, or situation to su

1.adjectiveC2
Definition

bringing bad results, or making it harder for a person, plan, or situation to succeed or improve.

Example

Heavy rain had an adverse effect on the tomato crop this summer.

adverse effect on + noun

The child had an adverse reaction after taking the cough medicine.

medical collocation: adverse reaction

Common collocations
  • adverse effect
  • adverse reaction
  • adverse weather
  • adverse publicity
  • adverse conditions
Synonyms
  • harmful

    plainer and more direct, especially for damage to health, safety, or the environment

  • detrimental

    very close in formal meaning, often stressing clear damage over time

  • unfavorable

    often about conditions, opinions, or decisions that are not on your side

  • damaging

    more direct and everyday; often suggests visible harm

Antonyms
  • beneficial

    formal opposite for something that helps or improves a situation

  • favorable

    opposite for conditions, opinions, or results that support success

  • helpful

    simpler everyday opposite

Grammar Patterns

adverse + noun

adverse effect on + noun

adverse reaction to + noun

Usage Note

Common in formal writing, especially before nouns such as effect, reaction, weather, conditions, publicity, or ruling. Distinguish from simple 'bad': adverse usually points to something that works against progress, health, business, or success.

Common Mistakes

She had an averse reaction to the medicine.
She had an adverse reaction to the medicine.
'adverse' is used for bad effects or conditions; 'averse' describes a person's dislike.
The storm adversely the football match.
The storm had an adverse effect on the football match.
'adverse' is an adjective, so use it with a noun such as 'effect' or 'weather'.

Word family

Synonym discussion

Sense: adjective/1

All four words describe something bad, but they focus differently. 'Harmful' is the plainest choice and often points to direct damage to health, safety, or the environment. 'Adverse' is more formal and appears often in medicine, law, business, and news reports, especially with nouns like 'effect', 'reaction', 'weather', and 'publicity'. 'Detrimental' is close to 'adverse' but sounds slightly more technical and often suggests lasting damage. 'Unfavorable' usually means that conditions, opinions, or decisions are not on your side, without always stressing harm. So smoke can be harmful to children, a tax ruling can have adverse effects on shops, and market conditions can be unfavorable for new businesses.

adverse ↗harmful ↗detrimental ↗unfavorable

Common collocations

Nouns

  • adverse effect
  • adverse reaction
  • adverse weather
  • adverse publicity
  • adverse ruling
  • adverse conditions

Adverbs

  • highly adverse
  • particularly adverse
  • potentially adverse

Phrases

  • have an adverse effect on
  • suffer adverse effects
  • an adverse reaction to a drug

Prepositions

  • adverse to (someone's interests)
  • adverse to growth

Etymology

LatinFrenchEnglish

'Adverse' came into English in the late Middle English period from French and Latin forms built on the idea of turning toward or against something. Its Latin source, 'adversus', meant 'turned against' as well as 'facing'. That image of something set against you later developed into the modern meaning of producing bad results or working against a person's interests.