adverse

[ ad-vurs, ad-vurs ]

adjective

1. unfavorable or antagonistic in purpose or effect:

   adverse criticism.

   Synonyms: unfriendly, inimical, hostile

   Antonyms: favorable

2. opposing one's interests or desire:

   adverse circumstances.

   Synonyms: catastrophic, calamitous, disastrous, unfortunate, unlucky, unfavorable

   Antonyms: favorable

3. being or acting in a contrary direction; opposed or opposing:

   adverse winds.

   Antonyms: favorable

4. opposite; confronting:

   the adverse page.

adverse

/ ˈædvɜːs; ædˈvɜːs /

adjective

1. antagonistic or inimical; hostile

   adverse criticism

2. unfavourable to one's interests

   adverse circumstances

3. contrary or opposite in direction or position

   adverse winds

4. See averse
   (of leaves, flowers, etc) facing the main stem Compare averse

Confusables Note

The adjectives adverse and averse are related both etymologically and semantically, each having “opposition” as a central sense. Adverse is seldom used of people but rather of effects or events, and it usually conveys a sense of hostility or harmfulness: adverse reviews; adverse winds; adverse trends in the economy. Related nouns are adversity and adversary: Adversities breed bitterness. His adversaries countered his every move. Averse is used of persons and means “feeling opposed or disinclined”; it often occurs idiomatically with a preceding negative to convey the opposite meaning “willing or agreeable,” and is not interchangeable with adverse in these contexts: We are not averse to holding another meeting. The related noun is aversion: She has a strong aversion to violence. Averse is usually followed by to, in older use occasionally by from.

Derived Forms

• adˈverseness, noun
• adˈversely, adverb

Other Words From

• ad·verse·ly adverb
• ad·verse·ness noun
• un·ad·verse adjective
• un·ad·verse·ness noun

Word History and Origins

Origin of adverse¹

First recorded in 1350–1400; Middle English, from Anglo-French, Old French advers, from Latin adversus “hostile” (past participle of advertere ), equivalent to ad- ad- + vert- “turn” + -tus past participle suffix, with -tt- giving rise to -s-

Word History and Origins

Origin of adverse¹

C14: from Latin adversus opposed to, hostile, from advertere to turn towards, from ad- to, towards + vertere to turn

Synonym Study

See contrary.

Example Sentences

The “plastic” antibodies saved mice from cobra venom, and healthy mice that received them had no adverse reactions, the team reported in PLOS Neglected Tropical Diseases.

From Science News

The company said there had been no serious adverse reactions among any of those receiving the vaccine.

From Fortune

Between 2015 to 2019, health-care professionals, patients, and manufacturers filed nearly 2,500 reports to the FDA about an adverse reaction to an excipient.

From Popular-Science

So far, Sinopharm reports that no one who has received its vaccines through the emergency program has experienced obvious adverse effects, and none have been infected with Covid-19.

From Vox

If the vaccine caused the illness — known as a serious adverse event — it could spell the end for AstraZeneca’s vaccine hopes.

From Science News

“Any time you put a foreign substance into anybody you have the potential for an adverse event,” Geisbert reminds.

From The Daily Beast

I think it's good that it doesn't look like there was any serious adverse event, I mean, nobody was hospitalized.

From The Daily Beast

Human trials of the Ebola vaccine have been temporarily shut down due to adverse side effects.

From The Daily Beast

However, just because a vaccine is replication-defective does not mean that you won't have an adverse event.

From The Daily Beast

For the individual patient, there is the potential for side effects or adverse reactions.

From The Daily Beast

At last his anxiety reached a point where he was positive that if he received an adverse decision, it would surely kill him.

From Project Gutenberg

He must have seen, long before November 1292, that an adverse decision was a foregone conclusion.

From Project Gutenberg

Clear as our case was to us the Conference seemed unconvinced, and we began to fear an adverse vote.

From Project Gutenberg

It is true that an adverse claimant cannot give any title to her husband's land that would bar her right thereto.

From Project Gutenberg

Adverse critics contended that he unduly protected the Filipino to the prejudice of the white manʼs interest.

From Project Gutenberg

Related Words

• conflicting
• detrimental
• disadvantageous
• inimical
• injurious
• negative
• unfortunate
• unfriendly

Adverse Vs. Averse

What's the difference between adverse and averse?

Adverse most commonly means unfavorable or hostile, as in adverse conditions, adverse weather, or adverse criticism. Averse means strongly opposed to or having a feeling of strong dislike toward something, as in I’m extremely averse to taking on debt.

Averse is often used in negative constructions, as in We are not averse to negotiations. It’s also used in the term risk-averse, meaning reluctant to take risks or tending to avoid risk.

Confusion can arise between the two terms because both are adjectives that involve unfavorableness or opposition. However, adverse typically describes circumstances, while averse typically describes the way someone feels toward something.

One way to remember which word is which is to remember that adverse, in a very general sense, means bad, which rhymes with the first part of the word. On the other hand, when you’re averse to something, you have a very strong opposition to it.

It may also be helpful to remember that the noun form of adverse is adversity, which means hostile or unfavorable conditions. The noun form of averse is aversion, meaning a strong feeling of dislike or opposition.

Here’s an example of adverse and averse used correctly in a sentence.

Example: I’m not averse to taking risks for the sake of adventure, but I just don’t think it’s safe to skydive in such adverse weather.

Want to learn more? Read the full breakdown of the difference between adverse and averse.

Quiz yourself on adverse vs. averse!

Should adverse or averse be used in the following sentence?

The medication had some _____ effects.