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.
Avoid reusing or reheating cooking oils to prevent harmful compounds.35 Taste and flavor: Canola, grapeseed, corn, soybean, safflower, and sunflower oils are ideal for sautéing or baking. Amy Brownstein, Verywell Health, 12 June 2025 Independent testing confirms that the supplement contains the ingredients listed on the label and is free from harmful contaminants. Nick Blackmer, Health, 12 June 2025 McFarland is facing charges of solicitation of a minor, transmission of harmful material to a minor and violation of probation. Devoun Cetoute, Miami Herald, 12 June 2025 Lights without these certifications may generate harmful byproducts, Taylor notes. Matt Fuchs, Time, 12 June 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 15 Jun. 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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