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.
Located in the stratosphere, the ozone layer acts like sunscreen, blocking potentially harmful ultraviolet energy from reaching our planet's surface. Doyle Rice, USA Today, 20 May 2025 Even apps like YouTube Kids can expose kids to harmful content. Anna Halkidis, Parents, 19 May 2025 Viscose usually requires harsh chemicals, but these sheets are Oeko-Tex certified, which means they're made without harmful chemicals and pesticides. Nena Farrell, Wired News, 19 May 2025 Customers confirm the quality, softness, and longevity of this pick, made from 100% cotton and Oeko-Tex certified to be free of a range of harmful chemicals. Julia Harrison, Architectural Digest, 19 May 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

Browse Nearby Words

Cite this Entry

“Harmful.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harmful. Accessed 23 May. 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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