harmful

adjective

harm·​ful ˈhärm-fəl How to pronounce harmful (audio)
Synonyms of harmfulnext
: of a kind likely to be damaging : injurious
harmfully
ˈhärm-fə-lē How to pronounce harmful (audio)
adverb
harmfulness noun

Synonyms

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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.
This can be extremely harmful to the lungs of at-risk people, including children whose lungs are still developing, pregnant women, older adults and those with asthma, chronic obstructive pulmonary disease or diabetes, according to the American Lung Assn. — Karen Garcia, Los Angeles Times, 20 Mar. 2025 Test results from Consumer Reports found potentially harmful chemicals in roughly half of the formula products. — Geoff Harris, Baltimore Sun, 20 Mar. 2025 Among her new charges are two counts of dissemination of matter harmful to minors and contributing to juvenile delinquency, according to multiple reports. — Mike Stunson, Kansas City Star, 19 Mar. 2025 Malicious actors on the same network can take advantage of security flaws on your device to install harmful software. — Kurt Knutsson, Cyberguy Report, Fox News, 18 Mar. 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

Rhymes for harmful

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Browse Nearby Words

harmful
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Cite this Entry

“Harmful.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harmful. Accessed 24 Mar. 2025.

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Kids Definition

harmful

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

Nglish: Translation of harmful for Spanish Speakers

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