harm·​ful | \ ˈhärm-fəl How to pronounce harmful (audio) \

Definition of harmful

: of a kind likely to be damaging : injurious

Keep scrolling for more

Other Words from harmful

harmfully \ ˈhärm-​fə-​lē How to pronounce harmfully (audio) \ 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

An incorrect interpretation could be seriously harmful to a deaf person in a setting such as a courtroom or doctor’s office, Maffucci and Voss said. Sophie Carson, Milwaukee Journal Sentinel, "Lawmaker who vowed no haircuts until sign language interpreter bill passed finally gets buzz cut as deaf community cheers," 2 July 2019 Protecting students Critics countered that the art is offensive and harmful to students, inappropriate for a school. Jill Tucker, SFChronicle.com, "School board faces mural dilemma: free speech or racial justice," 2 July 2019 Shark fishing naturally brings the apex predators closer to popular beaches and has the potential to create harmful or deadly situations for unsuspecting swimmers, according to the FWC. Joe Mario Pedersen, orlandosentinel.com, "New Florida law requires shark fishing permit; here are the details," 1 July 2019 Lawmakers in control of the state budget are eyeing multimillion-dollar cuts to county mental health care programs, reductions that advocates and other legislators say are hypocritical and harmful — and based upon flawed assumptions. oregonlive.com, "Oregon lawmakers approve pet projects, needed allocations on session’s final day," 30 June 2019 Until recently, social media platforms could feign ignorance about the scope and impact of harmful content on their sites. Alexander Heffner, WIRED, "Greed Is to Blame for the Radicalization of Social Media," 30 June 2019 These fungi are more of an aesthetic issue rather than harmful to plants. Jo Ellen Meyers Sharp, Indianapolis Star, "The Hoosier Gardener: Weather prime for fungus problems," 28 June 2019 And then there's the exposure to harmful UV rays and drying chlorine or salt water, which can put hair health at risk. Lauren Valenti, Vogue, "How to Get Your Best Summer Curls, According to Top Industry Pros," 28 June 2019 But fine-tuning the technology to better recognize black faces is only part of the process: Perfectly accurate technology could still be used to support harmful policing , which affect people of color. Sidney Fussell, The Atlantic, "The Strange Politics of Facial Recognition," 28 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'harmful.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of harmful

14th century, in the meaning defined above

Keep scrolling for more

Learn More about harmful

Dictionary Entries near harmful

harm's way







Statistics for harmful

Last Updated

8 Jul 2019

Look-up Popularity

Time Traveler for harmful

The first known use of harmful was in the 14th century

See more words from the same century

Keep scrolling for more

More Definitions for harmful



English Language Learners Definition of harmful

: causing or capable of causing damage or harm


harm·​ful | \ ˈhärm-fəl How to pronounce harmful (audio) \

Kids Definition of harmful

: causing or capable of causing harm : injurious Keep harmful substances away from children.

Other Words from harmful

harmfully \ -​fə-​lē \ adverb



Legal Definition of harmful

: of a kind likely to cause harm

Other Words from harmful

harmfully adverb
harmfulness noun

Keep scrolling for more

More from Merriam-Webster on harmful

Thesaurus: All synonyms and antonyms for harmful

Spanish Central: Translation of harmful

Nglish: Translation of harmful for Spanish Speakers

Britannica English: Translation of harmful for Arabic Speakers

Comments on harmful

What made you want to look up harmful? Please tell us where you read or heard it (including the quote, if possible).


food or victuals

Get Word of the Day daily email!

Test Your Vocabulary

Farm Idioms Quiz

  • cow coming home
  • What does 'poke' refer to in the expression 'pig in a poke'?
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

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