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.
The debate over the law centers on balancing accountability for harmful content with the risks of censorship and stifled innovation. Daryl Lim, The Conversation, 9 Apr. 2025 Shiny and minty, these balms provide a gloss-like effect while protecting your lips from the sun’s harmful rays. Jillian Dara, Travel + Leisure, 9 Apr. 2025 The agency's position is that there isn't enough scientific evidence to show these ingredients, as used in cosmetics, are harmful. Malaka Gharib, NPR, 8 Apr. 2025 Their research sheds new light on how the human body detects and reacts to intensely bitter compounds, some of which are not harmful despite their taste. Gordon G. Chang, MSNBC Newsweek, 8 Apr. 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 22 Apr. 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
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!