HARMFUL Synonyms: 90 Similar and Opposite Words

harmful

adjective

ˈhärm-fəl

Definition of harmful

as in detrimental

causing or capable of causing harm DDT has been proven to be extremely harmful to the environment

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Example Sentences

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.

Recent Examples of harmful Pro-vaccine nonprofits have published accounts of life with measles before the vaccine was developed to show how harmful the virus can be. — Nicholas Florko, STAT, 21 Oct. 2026 Temperature control is an important aspect of food safety in restaurants and grocery stores, because harmful bacteria can grow quickly. — Eva Flowe october 21, Charlotte Observer, 21 Oct. 2026 Such laws would require third-party audits of social media algorithms to identify any harmful patterns, such as serving eating-disorder content to young girls more than to other groups. — Allison Parshall, Scientific American, 20 Oct. 2026 Many of those officials have reported the letters contained white powdery substances, though none have been confirmed to be harmful. — Olivia Young, CBS News, 20 Oct. 2026 See All Example Sentences for harmful

Recent Examples of Synonyms for harmful

Adjective

The company still faces numerous personal injury claims and a separate federal case involving a group of nationwide school districts that also focus on allegations that apps like Instagram have had detrimental effects on the well being of children.

— Jonathan Vanian, CNBC, 21 Oct. 2026
Often, those firms’ IT heads think those changes are detrimental.

— Scharon Harding, ArsTechnica, 21 Oct. 2026

Definition of detrimental

Adjective

Trump could decide that appearing powerless as Iranian attacks push up prices is more damaging than another round of military strikes.

— Ali Vaez, Time, 21 Oct. 2026
Lycopene can help protect blood vessels from the damaging effects of unstable molecules known as free radicals.

— MD Published, Verywell Health, 17 Oct. 2026

Definition of damaging

Adjective

In November 2021, crew members took shelter inside their spacecraft after a Russian anti-satellite weapons test created a dangerous cloud of debris.

— Kurt Knutsson, FOXNews.com, 25 Oct. 2026
In 2015, Chicago’s public health department identified three cases of invasive meningococcal disease, a highly dangerous pathogen that can kill within hours.

— Julie Morita, Time, 25 Oct. 2026

Definition of dangerous

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harmers

harmful

harmfulness

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“Harmful.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/harmful. Accessed 27 Oct. 2026.

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Synonyms of harmful

adjective

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