ad·​verse | \ ad-ˈvərs How to pronounce adverse (audio) , ˈad-ˌvərs \

Essential Meaning of adverse

: bad or unfavorable : not good adverse criticism/remarks He had an adverse reaction to the medicine. [=he reacted badly to the medicine; the medicine had a bad effect on him] See More ExamplesMany fear that budget cuts will have an adverse [=damaging] effect on education. adverse circumstances/conditions/weather The drug has no adverse [=harmful] side effects.Hide

Full Definition of adverse

1 : acting against or in a contrary direction : hostile hindered by adverse winds
2a : 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

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Other Words from adverse

adverseness noun

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.

Examples of adverse in a Sentence

The Bankruptcy Code requires that debtor's counsel be disinterested and not have an interest adverse to the estate. Lawyers Weekly USA, 4 Oct. 1999 On more than one occasion his decrees provoked riots, and there were those who voiced adverse opinions on the Duke in public. — Alison Weir, The Princes in the Tower, 1992 The plant tolerates adverse conditions … — Dave Dunn, Fine Gardening, January/February 1991 all the adverse publicity really caused the movie star's popularity to suffer the adverse effects of the drug are too severe to allow it to be marketed
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Recent Examples on the Web Energy from Setbacks Ultra-high achievers have often gone through an adverse life event, such as losing a parent or loved one, parental divorce, or an unsettled environment. Kumar Mehta, Forbes, 19 Oct. 2021 For example, when patients are at higher risk for any adverse event, they are moved closer to nurses’ stations and often have additional precautions in place for their care. Randy Gross,, 26 Aug. 2021 A third of the women 65 and older in the breast cancer trial had to permanently get off Afinitor because of a serious adverse event. John Fauber And Coulter Jones, Milwaukee Journal Sentinel, 23 Aug. 2021 In recent years, scientists have begun to recognize that the practice of gratitude can be a key driver of post-traumatic growth after an adverse event, and that gratitude can be a healing force. Scott Barry Kaufman, The Atlantic, 18 Aug. 2021 The second reason is if somebody from a prior vaccination had a rare, adverse event called Guillain-Barré. al, 13 Aug. 2021 After the Star Tribune pointed out a half dozen reports of potential problems, an FDA official said the agency would continue to examine its database of adverse event reports, which are unproven reports of patient harm or device malfunctions. Joe Carlson, Star Tribune, 23 July 2021 Public health officials investigate adverse event reports submitted to VAERS. Bayliss Wagner, USA TODAY, 28 June 2021 No single adverse event occurred in more than 1% of the vaccine group. Morgan Winsor, ABC News, 14 June 2021

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.

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First Known Use of adverse

14th century, in the meaning defined at sense 1

History and Etymology for 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 advert entry 1

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Time Traveler for adverse

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The first known use of adverse was in the 14th century

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Last Updated

23 Oct 2021

Cite this Entry

“Adverse.” Dictionary, Merriam-Webster, Accessed 27 Oct. 2021.

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More Definitions for adverse


ad·​verse | \ ad-ˈvərs How to pronounce adverse (audio) \

Kids Definition of adverse

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

Other Words from adverse

adversely adverb Bad weather adversely affected attendance at the fair.


ad·​verse | \ ad-ˈvərs, ˈad-ˌvərs How to pronounce adverse (audio) \

Legal Definition of adverse

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

More from Merriam-Webster on adverse

Nglish: Translation of adverse for Spanish Speakers

Britannica English: Translation of adverse for Arabic Speakers


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