harmful

adjective

harm·​ful ˈhärm-fəl How to pronounce harmful (audio)
Synonyms of harmfulnext
: of a kind likely to be damaging : injurious
harmful chemicals
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.
While skepticism toward artificial intelligence is understandable, dismissing AI as inherently harmful overlooks both history and reality. Arkansas Online, 27 Jan. 2026 Regulators will examine whether Grok is living up to its obligations under the Digital Services Act, the bloc’s wide-ranging rulebook for keeping internet users safe from harmful content and products. Kelvin Chan, Chicago Tribune, 26 Jan. 2026 Brazil issued formal recommendations to xAI to rein in harmful content, while the Philippines briefly blocked Grok before restoring access after safety fixes were promised. The Ai Insider, Interesting Engineering, 26 Jan. 2026 These harmful chemicals aren’t easily removed by commercial filters. Shi En Kim, AZCentral.com, 26 Jan. 2026 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 28 Jan. 2026.

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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