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 next

as in harmful

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

Synonyms & Similar Words

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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 In July of last year Steyer sent out a tweet criticizing rent control for its deleterious and counterproductive effects. —

Rafael Perez, Oc Register, 1 Mar. 2026 Conversely, cannabis appears to be especially deleterious to the cognitive and psychological well-being of young people. —

Alexander Nazaryan, New Yorker, 29 Jan. 2026 Studies have shown that routine use of AI has a deleterious impact on cognition, creativity, recall, and critical thinking. —

Krista Kafer, Denver Post, 25 Jan. 2026 Virtually no one’s immune from their deleterious effects, since they’re found in a wide variety of everyday products. —

Editorial, Boston Herald, 11 Jan. 2026 See All Example Sentences for deleterious

Recent Examples of Synonyms for deleterious

Adjective

But others say research in Australia has shown that age verification is difficult to enforce, and that a blanket ban seemed to be a snap decision that does not address a deeper problem — the way social media algorithms push harmful content to young people.

— ABC News, ABC News, 15 June 2026
There were also die-offs of seals, sea lions and marine birds, Leising said, probably from a combination of a lack of food and harmful algal blooms, and less food out there for baleen whales.

— Los Angeles Times, Los Angeles Times, 15 June 2026