del·​e·​te·​ri·​ous | \ ˌde-lə-ˈtir-ē-əs How to pronounce deleterious (audio) \

Definition of deleterious

: harmful often in a subtle or unexpected way deleterious effects deleterious to health

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Other Words from deleterious

deleteriously adverb
deleteriousness noun

Choose the Right Synonym for deleterious

pernicious, baneful, noxious, deleterious, detrimental mean exceedingly harmful. pernicious implies irreparable harm done through evil or insidious corrupting or undermining. the claim that pornography has a pernicious effect on society baneful implies injury through poisoning or destroying. the baneful notion that discipline destroys creativity noxious applies to what is both offensive and injurious to the health of a body or mind. noxious chemical fumes deleterious applies to what has an often unsuspected harmful effect. a diet found to have deleterious effects detrimental implies obvious harmfulness to something specified. the detrimental effects of excessive drinking

Examples of deleterious in a Sentence

In developing countries, the imposition of boundaries around national parks and protected areas has been deleterious for both people and wildlife. — Kristin B. Gunther, Association of American Geographers, 2002 Most everyone now knows the action of pressing mouse keys is far more deleterious to the tender structures of the wrist and hand than typing is. — Michael Finley, Albany (New York) Times-Union, 2 Sept. 1998 This skewed allocation of resources away from those most in need, in turn, insures that many young people from low-income families will continue to be shut out of the economy, with obvious deleterious family and social consequences. — Iris C. Rotberg, Education Week, 9 Mar. 1994 For as James Keirans pointed out to me, ticks are the world's most notorious carriers of the agents of diseases that strike animals, wild and domestic. And they rank second only to mosquitoes in their deleterious effect on humans. — Edwards Park, Smithsonian, January 1987 The chemical is deleterious to the environment. The drug has no deleterious effects on patients.
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Recent Examples on the Web For our purposes, the most notable deleterious effect is that the blasts themselves would heat up the planet, counteracting the stated goal of reversing global warming. Maddie Bender, Scientific American, 18 June 2021 Despite our efforts and those of countless other organizations, stark disparities in income and race remain and have a deleterious effect on educational attainment. Raymond Pierce, Forbes, 16 June 2021 But those concerns often conveniently overlooked the tatty crud regularly published in the country’s reactionary right-wing tabloids, many of which are owned by Murdoch, which have had a profoundly deleterious effect on British society for decades. Alex Shephard, The New Republic, 21 June 2021 The tax increases could have a deleterious impact on the economy, which otherwise has improved at a greater-than-expected rate than initially forecast when Biden became president. W. James Antle Iii, Washington Examiner, 29 Apr. 2021 But that marketing concept doesn’t distract from Hollywood’s deleterious intention; Stone and her filmmaker cohorts can barely disguise it. Armond White, National Review, 28 May 2021 The message comes at a time when the Biden Administration has done much both to stem the pandemic in the United States and to reverse the deleterious approach of the Trump White House. Jerome Groopman, The New Yorker, 29 Mar. 2021 Even lawns, frequently derided for costly and environmentally deleterious fertilizer and herbicide applications, contribute in a positive way. cleveland, 5 Mar. 2021 Mounting evidence shows that media and technology use predict deleterious psychological and physiological outcomes, especially among young people. Arthur C. Brooks, The Atlantic, 22 Oct. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'deleterious.' 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 deleterious

1587, in the meaning defined above

History and Etymology for deleterious

Greek dēlētērios, from dēleisthai to hurt

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Time Traveler for deleterious

Time Traveler

The first known use of deleterious was in 1587

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Last Updated

29 Jul 2021

Cite this Entry

“Deleterious.” Dictionary, Merriam-Webster, Accessed 30 Jul. 2021.

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More Definitions for deleterious



English Language Learners Definition of deleterious

formal : damaging or harmful


del·​e·​te·​ri·​ous | \ ˌdel-ə-ˈtir-ē-əs How to pronounce deleterious (audio) \

Medical Definition of deleterious

: harmful often in a subtle or an unexpected way the deleterious effects of radiation and chemotherapy on the marrow— Christine Gorman deleterious genes

More from Merriam-Webster on deleterious

Nglish: Translation of deleterious for Spanish Speakers

Britannica English: Translation of deleterious for Arabic Speakers


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