harmful

adjective

harm·​ful ˈhärm-fəl How to pronounce harmful (audio)
: of a kind likely to be damaging : injurious
harmfully 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
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.
Studies have shown that testers can harbor harmful bacteria, including Staphylococcus aureus (a common cause of styes and other infections), E. coli, yeast, and mold. Mark Joseph, Newsweek, 24 Feb. 2025 Organic farms use natural farming methods to keep the soil, water, and environment free from potentially harmful chemicals.7 Similarities Grass-fed and organic foods share a commitment to natural farming. Chelsea Rae Bourgeois, Rdn, Ld, Health, 24 Feb. 2025 Throwing our economic growth in reverse by imposing harmful tariffs and repealing existing laws will only leave the U.S. auto industry in the dust. Energy Innovation: Policy and Technology, Forbes, 23 Feb. 2025 In its earliest days, vaping was broadly pitched as a less harmful alternative to cigarettes, one that could help people break a habit that everyone knows is horrible for human lungs and hearts. New York Daily News Editorial Board, New York Daily News, 23 Feb. 2025 See All Example Sentences for harmful

Word History

First Known Use

14th century, in the meaning defined above

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

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Cite this Entry

“Harmful.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harmful. Accessed 3 Mar. 2025.

Kids Definition

harmful

adjective
harm·​ful ˈhärm-fəl How to pronounce harmful (audio)
: causing damage : injurious
harmfully adverb
harmfulness noun

Legal Definition

harmful

adjective
harm·​ful
: of a kind likely to cause harm
harmfully adverb
harmfulness noun

More from Merriam-Webster on harmful

Last Updated: - Updated example sentences
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