adjective ad·verse \ ad-ˈvərs , ˈad-ˌ \
|Updated on: 14 Aug 2018

Definition of adverse

1 : acting against or in a contrary direction : hostile
  • hindered by adverse winds
2 a : opposed to one's interests
  • an adverse verdict
  • heard testimony adverse to their position
; especially : unfavorable
  • adverse criticism
b : causing harm : harmful
  • adverse drug effects
3 archaic : opposite in position





Examples of adverse in a Sentence

  1. The Bankruptcy Code requires that debtor's counsel be disinterested and not have an interest adverse to the estate. Lawyers Weekly USA4 Oct. 1999
  2. On more than one occasion his decrees provoked riots, and there were those who voiced adverse opinions on the Duke in public. —Alison WeirThe Princes in the Tower1992
  3. The plant tolerates adverse conditions … —Dave DunnFine GardeningJanuary/February 1991
  4. all the adverse publicity really caused the movie star's popularity to suffer

  5. the adverse effects of the drug are too severe to allow it to be marketed

Recent Examples of adverse from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'adverse.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

adverse vs. averse

Many people find themselves confused when faced with the choice between adverse and averse. While these two adjectives have many similarities, they are not used interchangeably.

If you want to describe a negative reaction to something (such as a harmful side effect from medication) or dangerous meteorological conditions (such as a snowstorm), adverse is the correct choice; you would not say that you had an averse reaction to medication or that there was averse weather.

Averse is most commonly followed by the preposition to (as in "she is averse to shellfish"), but not in every case; you can, for example, describe someone as “risk averse." Normally, averse to signifies a degree of dislike and avoidance, but when preceded by the word not (as in “he was not averse to having another drink”), it may be used as a pointedly understated way to express an interest in something.

In short, adverse tends to be used to describe effects, conditions, and results; while averse refers to feelings and inclinations.

Origin and Etymology of adverse

Middle English, borrowed from Anglo-French advers, borrowed from Latin adversus "turned toward, facing, opposed," from past participle of advertere "to turn toward, direct" — more at 1advert

ADVERSE Defined for English Language Learners


Definition of adverse for English Language Learners

  • : bad or unfavorable : not good

ADVERSE Defined for Kids


adjective ad·verse \ ad-ˈvərs \

Definition of adverse for Students

1 : acting against or in an opposite direction
  • adverse winds
2 : not helping or favoring
  • adverse circumstances


  • Bad weather adversely affected attendance at the fair.

Law Dictionary


adjective ad·verse \ ad-ˈvərs, ˈad-ˌvərs \

legal Definition of adverse

: opposed to one's interests : operating to one's detriment
  • an adverse verdict

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very hard to disturb or upset

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