DELETERIOUS Synonyms: 90 Similar and Opposite Words

Q: How is the word 'deleterious' different from other adjectives like it?

Some common synonyms of deleterious are baneful , detrimental , noxious , and pernicious . While all these words mean "exceedingly harmful," deleterious applies to what has an often unsuspected harmful effect. // a diet found to have deleterious effects

Q: When is 'baneful' a more appropriate choice than 'deleterious'?

The synonyms baneful and deleterious are sometimes interchangeable, but baneful implies injury through poisoning or destroying. // the baneful notion that discipline destroys creativity

Q: When would 'detrimental' be a good substitute for 'deleterious'?

The words detrimental and deleterious are synonyms, but do differ in nuance. Specifically, detrimental implies obvious harmfulness to something specified. // the detrimental effects of excessive drinking

Q: When can 'noxious' be used instead of 'deleterious'?

The meanings of noxious and deleterious largely overlap; however, noxious applies to what is both offensive and injurious to the health of a body or mind. // noxious chemical fumes

Q: Where would 'pernicious' be a reasonable alternative to 'deleterious'?

The words pernicious and deleterious can be used in similar contexts, but pernicious implies irreparable harm done through evil or insidious corrupting or undermining. // the claim that pornography has a pernicious effect on society

deleterious

adjective

ˌde-lə-ˈtir-ē-əs

Definition of deleterious

as in harmful

causing or capable of causing harm nicotine has long been recognized as a deleterious substance

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How is the word deleterious different from other adjectives like it?

Some common synonyms of deleterious are baneful, detrimental, noxious, and pernicious. While all these words mean "exceedingly harmful," deleterious applies to what has an often unsuspected harmful effect.

a diet found to have deleterious effects

When is baneful a more appropriate choice than deleterious?

The synonyms baneful and deleterious are sometimes interchangeable, but baneful implies injury through poisoning or destroying.

the baneful notion that discipline destroys creativity

When would detrimental be a good substitute for deleterious?

The words detrimental and deleterious are synonyms, but do differ in nuance. Specifically, detrimental implies obvious harmfulness to something specified.

the detrimental effects of excessive drinking

When can noxious be used instead of deleterious?

The meanings of noxious and deleterious largely overlap; however, noxious applies to what is both offensive and injurious to the health of a body or mind.

noxious chemical fumes

Where would pernicious be a reasonable alternative to deleterious?

The words pernicious and deleterious can be used in similar contexts, but pernicious implies irreparable harm done through evil or insidious corrupting or undermining.

the claim that pornography has a pernicious effect on society

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of deleterious The primary question is whether this crowded field of new entrants is actually accomplishing anything, or whether its members are simply tripping over one another with deleterious impact. — Jeffrey Sonnenfeld, Time, 28 June 2026 France is a climate-conscious population; there has been a strong aversion to air-conditioning, understood, rightly, as a Band-Aid that might hasten the deleterious resolution of the climate crisis. — Doreen St. Félix, New Yorker, 27 June 2026 There are already many common-sense proposals to fix the influence and deleterious effects of social media on society as a whole. — Linh Tat, Oc Register, 5 May 2026 The guidance has evolved over the years, but the most recent studies have found that any level of drinking can have deleterious effects. — Lois K. Solomon, Sun Sentinel, 22 Apr. 2026 See All Example Sentences for deleterious

Recent Examples of Synonyms for deleterious

Adjective

Child development experts have noted teenagers are more susceptible to social comparison than adults, so products that reward popularity can be more harmful to their mental health.

— ABC News, ABC News, 19 Aug. 2026
Beneficial bacteria also provide colonization resistance, competing with harmful microbes for nutrients and attachment sites while producing substances that inhibit their growth.

— Encyclopedia Britannica, Encyclopedia Britannica, 19 Aug. 2026

Definition of harmful

Adjective

Then England attracted adverse attention for openly drinking in the Queensland resort of Noosa when 2-0 down in a one-sided Ashes series in Australia.

— Paul Newman, New York Times, 23 Aug. 2026
Women with high occupational heat exposure were roughly twice as likely to suffer a miscarriage or stillbirth as those working in cooler conditions, and faced elevated risks of adverse birth outcomes overall.

— Catarina Rolfsdotter-Jansson, Forbes.com, 22 Aug. 2026

Definition of adverse

Adjective

The greatest risk from the storms will be from damaging winds and heavy downpours.

— Rachael Jay, CBS News, 20 Aug. 2026
Although both helped mitigate the effects of the gas, urine offered some degree of chemical protection because its ammonia partially neutralized the chlorine, reducing the gas’s damaging and potentially lethal effects on the lungs.

— Encyclopedia Britannica, Encyclopedia Britannica, 19 Aug. 2026

Definition of damaging

Adjective

The desert’s location on the southern border has led to many migrants attempting to cross it by using dangerous backcountry routes, the experts said.

— Emma Tucker, CNN Money, 24 Aug. 2026
Rather, this is a dangerous, shape-shifting synthetic entity that ravaged their entire planet.

— Siddhant Adlakha, Vulture, 24 Aug. 2026

Definition of dangerous

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“Deleterious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/deleterious. Accessed 25 Aug. 2026.

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Synonyms of deleterious

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