harmful

adjective
harm·​ful | \ ˈhärm-fəl How to pronounce harmful (audio) \

Definition of harmful

: of a kind likely to be damaging : injurious

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Other Words from harmful

harmfully \ ˈhärm-​fə-​lē How to pronounce harmful (audio) \ adverb
harmfulness noun

Examples of harmful in a Sentence

DDT has been proven to be extremely harmful to the environment.
Recent Examples on the Web Depending on its source, sea salt can contain some or many beneficial trace minerals, but also potentially harmful pollutants. Ana Sanchez, chicagotribune.com, "The best salt," 23 Dec. 2020 Beta carotene functions as an antioxidant, a compound that helps defend your cells from damage caused by potentially harmful molecules called free radicals. USA Today, "How to strengthen your immune system this winter," 17 Dec. 2020 When the ultimate goal is to breathe clean air free of potentially harmful particles, an air purifier is probably not the best place to skimp. Popular Science, "Best air purifier: Fight allergens, smoke, and germs for cleaner indoor air," 16 Dec. 2020 This year of Covid-19 shutdowns has forced us to rethink the counterintuitive and potentially harmful practice of allowing strangers to touch our children for the sake of a laugh, the snap of a photo. Allison Hope, CNN, "Socially distanced Santa is the best thing to happen to Christmas," 15 Dec. 2020 Her hiring helped improve Google's reputation as a company that recruits top Black researchers and questions potentially harmful uses of AI technology. Jessica Guynn, USA TODAY, "Google ouster of top AI researcher Timnit Gebru draws sharp new scrutiny of how it treats Black employees," 12 Dec. 2020 Recent studies have even implicated tire treads as potentially harmful. Kurtis Alexander, SFChronicle.com, "New research explains why salmon are dying in the Pacific Northwest. The danger lurks in California, too," 3 Dec. 2020 The site is also one of 74 where the EPA admits that potentially harmful toxins remain uncontrolled, even though LCP Chemical has been in the national cleanup program since 1996. NBC news, "A growing toxic threat — made worse by climate change," 24 Sep. 2020 But Cerveza Patagonia, a company that brews premium beer from the Patagonia region of South America, wants to protect your trees from potentially harmful hurricanes this year. Andrea Romano, Travel + Leisure, "This Beer Company Will Replant Your Trees If They’re Damaged by a Hurricane," 23 Sep. 2020

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

14th century, in the meaning defined above

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Time Traveler for harmful

Time Traveler

The first known use of harmful was in the 14th century

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Statistics for harmful

Last Updated

9 Jan 2021

Cite this Entry

“Harmful.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harmful. Accessed 20 Jan. 2021.

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More Definitions for harmful

harmful

adjective
How to pronounce harmful (audio)

English Language Learners Definition of harmful

: causing or capable of causing damage or harm

harmful

adjective
harm·​ful | \ ˈhärm-fəl How to pronounce harmful (audio) \

Kids Definition of harmful

: causing or capable of causing harm : injurious Keep harmful substances away from children.

Other Words from harmful

harmfully \ -​fə-​lē \ adverb

harmful

adjective
harm·​ful

Legal Definition of harmful

: of a kind likely to cause harm

Other Words from harmful

harmfully adverb
harmfulness noun

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Comments on harmful

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