harmful

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

Definition of harmful

: of a kind likely to be damaging : injurious

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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

That makes your nose one of the first lines of defense for keeping potentially harmful particles out of your lungs, Erich Voigt, M.D., clinical associate professor and chief of general/sleep otolaryngology at NYU Langone Health, tells SELF. Carolyn L. Todd, SELF, "Quick Question: Why Do We Sneeze?," 8 Mar. 2019 As long as guidelines for spraying chemicals are followed there should not be any harmful effects on humans or animals. Patricia Dillon, Houston Chronicle, "Montgomery County officials find 38 cases of mosquitoes with West Nile Virus; urge taking precautions," 6 July 2018 But take note: This rule applies for meat stored at exactly 0°F without fluctuation — it must be uniformly frozen at that temperature to keep harmful bacteria away. Christina Oehler, Woman's Day, "This Is How Long Frozen Meat Is Good For," 22 Jan. 2019 The researchers found samples of Brucella melitensis, which is a harmful bacteria that causes the disease brucellosis. Avery Thompson, Popular Mechanics, "Researchers Find 3,000 Year Old Cheese," 20 Aug. 2018 The researchers believe the conductive material could be used for sensors that tell you when food is no longer fresh and even whether harmful bacteria are present. 19. Gemma Tarlach, Discover Magazine, "20 Things You Didn't Know About ... Graphene," 13 Aug. 2018 Combining certain antibiotics could help them pack a one-two punch against harmful bacteria, according to a new study published Wednesday in Nature. Megan Thielking, STAT, "As drug resistance grows, combining antibiotics could turn up new treatments," 4 July 2018 The Canadian province of Manitoba sued in 2002 over concerns about the possible transfer of harmful bacteria or other agents to the Hudson Bay Basin. Blake Nicholson, The Seattle Times, "US, Canada reach deal on disputed $244M water project," 26 June 2018 Jamison's skin can't shed harmful bacteria normally — even a small cut leaves him vulnerable to life-threatening infections. Ashley May, USA TODAY, "Mom bathes 1-year-old son with rare skin disorder in bleach to keep him alive," 21 June 2018

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.

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First Known Use of harmful

14th century, in the meaning defined above

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Dictionary Entries near harmful

harm's way

harman

harmattan

harmful

harmless

Harmolita

harmonia

Statistics for harmful

Last Updated

18 Mar 2019

Look-up Popularity

Time Traveler for harmful

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

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More Definitions for harmful

harmful

adjective

English Language Learners Definition of harmful

: causing or capable of causing damage or harm

harmful

adjective
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

harmful

adjective
harm·​ful

Legal Definition of harmful

: of a kind likely to cause harm

Other Words from harmful

harmfully adverb
harmfulness noun

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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

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