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 Douglas claims the company failed to use safe food storage, handling and preparation practices, failed to inspect food and kitchen conditions for contamination and failed to eliminate harmful bacteria before serving the meal. — Anthony Thompson, USA Today, 25 Aug. 2026 Focus on an actual harmful person, not the guy who everyone in Hollywood knows is hyper-intelligent, empathetic and talented. — Tommy McArdle, PEOPLE, 24 Aug. 2026 Michael Harte, 54, of Terryville, has been arrested and charged on a warrant with harmful communication with a minor, according to the Naugatuck Police Department. — Stephen Underwood, Hartford Courant, 23 Aug. 2026 Pests or salt buildup in soil can stress pothos; use insecticidal soap or flush or replace soil to remove harmful deposits. — Andy Wilcox, Better Homes & Gardens, 22 Aug. 2026 See All Example Sentences for harmful

Recent Examples of Synonyms for harmful

Adjective

Being full of yourself isn’t detrimental but necessary for survival.

— Angelica Jade Bastién, Vulture, 27 Aug. 2026
The settlement also requires limits on features that some experts believe are detrimental to teenagers’ self-esteem and self-image.

— Kaitlyn Tiffany, The Atlantic, 26 Aug. 2026

Definition of detrimental

Adjective

Missing, say, 30 games would likely not be as damaging as missing half a season, or a whole season.

— Evan Drellich, New York Times, 26 Aug. 2026
Strong El Niño events, such as the one revving up in the tropical Pacific, have rarely spared the Golden State from significant and damaging consequences.

— Andrew Freedman, CNN Money, 25 Aug. 2026

Definition of damaging

Adjective

Ustel said the ferry faced adverse weather conditions and began taking in water just 15 minutes after departure.

— ABC News, ABC News, 30 Aug. 2026
The report identified adverse effects on dozens of historic properties, including the Lincoln Memorial, Washington Monument and other landmarks.

— Amelia Lucas, CNBC, 29 Aug. 2026

Definition of adverse

Adjective

Poor Anton has been left out of the drama all day, an effort by Billie and Samir to prevent an already bad futzing from escalating to something severe, and that’s never where Anton likes to be.

— Ben Rosenstock, Vulture, 28 Aug. 2026
Although rarely seen, its reemergence earlier this summer is a signal of how bad the region’s ongoing drought has gotten, as well as a warning for the difficult months ahead.

— Andrew Paul, Popular Science, 27 Aug. 2026

Definition of bad

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harmful

harmfulness

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“Harmful.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/harmful. Accessed 1 Sep. 2026.

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Synonyms of harmful

adjective

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