harmful

adjective

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

Example Sentences

DDT has been proven to be extremely harmful to the environment.
Recent Examples on the Web The harsh punishment against Li shocked some stand-up comedy fans, who did not find Li’s words particularly offensive or harmful. Nectar Gan, CNN, 26 May 2023 Now, researchers have discovered a new chemical that selectively kills harmful nematodes with a much lower risk of toxicity to humans and other creatures. Byerik Stokstad, science.org, 25 May 2023 The 17PinHut Elevated Dog Bed with Canopy takes this concept to the next level with its convenient sun shade that will keep your dog cool and protected from harmful UV rays. Amber Smith, Discover Magazine, 24 May 2023 Hector also noted Act 612, which prohibits the distribution of harmful materials to minors. Paige Eichkorn, Arkansas Online, 17 May 2023 And both processes use antibiotics and preservatives that can be harmful to humans, Russek said. Cheryl V. Jackson, The Indianapolis Star, 16 May 2023 The teacher was arrested for terrorist threats and exposing a child to harmful material, descriptions or narrations — both felonies. Alex Groth, Journal Sentinel, 15 May 2023 Nearly 90% say tech companies should take steps to prevent their AI tools from creating harmful content and from generating antisemitic or extremist images and support congressional efforts to intervene. Jessica Guynn, USA TODAY, 15 May 2023 The center’s scientists use modeling, simulation, and real-world data to pinpoint where those hazards are in space and time, where the harmful elements will soon travel, and what can be done. Sarah Scoles, Popular Science, 11 May 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'harmful.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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

Dictionary Entries Near harmful

Cite this Entry

“Harmful.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harmful. Accessed 4 Jun. 2023.

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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