del·​e·​te·​ri·​ous | \ˌde-lə-ˈtir-ē-əs \

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

Musk’s behavior this summer has compounded the deleterious effect of technical problems in late March and early April, including a deadly autopilot crash, a Model S recall and production target misses. Rani Molla, Recode, "Elon Musk’s summer of bad behavior hasn’t affected Tesla’s sales, but it has hurt its reputation," 10 Oct. 2018 Add to that the potentially deleterious effects of tariffs being levied by President Donald Trump, and 2018 is quite a challenging year for the family farming business. The Aegis, "Roller coaster ride [Editorial]," 13 July 2018 No government has ever before sought to impose such a sweeping privacy control, perhaps because of the obviously deleterious effects on law enforcement. Brian E. Finch And, WSJ, "The EU’s Gift to Cybercriminals," 28 May 2018 Reports have have been trickling in for weeks in about the deleterious effect the president’s economic aggression is having on American businesses, from pork producers to fuel cell manufacturers. Benjamin Hart, Daily Intelligencer, "Harley-Davidson Announces It Will Move Some Operations to Europe Amid Trade War," 25 June 2018 While there's no clear connection between Spade's and Bourdain's deaths, high-profile suicides could have a deleterious effect on people experiencing emotional or psychological hardships, potentially leading to a contagion effect. Julyssa Lopez, Glamour, "How to Spot Signs of Suicide—and What You Can Do to Help," 8 June 2018 Adami has been arrested and charged with distributing food containing noxious/deleterious material. CBS News, "Pizza maker put suspected rat poison in the cheese, police say," 7 June 2018 But ironically enough, that same legislation is creating ripples in some housing markets that could prove particularly deleterious to second-home owners. Chris Taylor, Fortune, "Why Your Summer House Could Be a Shaky Investment," 29 May 2018 Strengthening mental-health services in emergency departments may relieve some of the deleterious effects of psychiatric boarding. Nathaniel Morris,, "Even suicidal patients are put on the ER wait list," 23 May 2018

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

1643, in the meaning defined above

History and Etymology for deleterious

Greek dēlētērios, from dēleisthai to hurt

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Last Updated

14 Nov 2018

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Time Traveler for deleterious

The first known use of deleterious was in 1643

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More Definitions for deleterious



English Language Learners Definition of deleterious

: damaging or harmful


del·​e·​te·​ri·​ous | \ˌdel-ə-ˈtir-ē-əs \

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

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