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 harmfully (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 The state decided to launch the campaign to highlight an American Medical Association study that documented the harmful effects of marijuana use by youths, said Lynn Sutfin, spokeswoman for the department. Kathleen Gray, Detroit Free Press, "State health department spends $300K on anti-marijuana public service announcements," 17 Jan. 2020 But this gene and others may have had harmful side effects that remained invisible until the sooty, smoky modern age. Carl Zimmer, New York Times, "Why Is Air Pollution So Harmful? DNA May Hold the Answer," 13 Jan. 2020 But the cream also helps prevent the harmful effects of free radicals, thanks to antioxidant botanical super lotus, plus known hydrator hyaluronic acid. Beth Janes, Marie Claire, "These Products Will Save Your Skin from Its Biggest Stressors," 9 Jan. 2020 Opponents said they were concerned that exhaust from the station could cause harmful health effects on nearby residents, most of whom are African American. Washington Post, "Court tosses permit for Atlantic Coast Pipeline station," 7 Jan. 2020 Venomous and poisonous animals both use toxins—substances that cause substantial, harmful physiological effects at small doses—to defend themselves or subdue prey. National Geographic, "What’s the difference between a poisonous and venomous animal?," 7 Jan. 2020 Concern about the potential harmful effects of video game and social-media overuse by children may mean this never happens. Mark Milian, Houston Chronicle, "Flying cars, hyperloops and the other 2020 tech predictions that didn’t pan out," 3 Jan. 2020 Concern about the potential harmful effects of video game and social-media overuse by children may mean this never happens. Fortune, "Flying Cars, Hyperloops and the Other 2020 Tech Predictions That Didn’t Pan Out," 27 Dec. 2019 The department should work with local housing authorities to remedy the issue as soon as possible to protect residents from the potentially harmful effects of radon exposure. oregonlive, "Congressional drumbeat grows louder for radon protections after Oregonian investigation," 21 Dec. 2019

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

21 Jan 2020

Cite this Entry

“Harmful.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/harmful. Accessed 21 January 2020.

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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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More from Merriam-Webster on harmful

Thesaurus: All synonyms and antonyms for harmful

Spanish Central: Translation of harmful

Nglish: Translation of harmful for Spanish Speakers

Britannica English: Translation of harmful for Arabic Speakers

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