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 While much of the AI safety debate has centered on losing control of AI, Altman said restricting access to AI too severely in the name of safety could be harmful too. — Marco Quiroz-Gutierrez, Fortune, 5 Oct. 2026 Cutting back on sugar starves the harmful bacteria that thrive in both regions. — Hanna Wickes, Charlotte Observer, 5 Oct. 2026 Cutting sugar starves the harmful bacteria that thrive in both the gut and the mouth. — Hanna Wickes, Kansas City Star, 5 Oct. 2026 The company has also been sued by the parents of kids who took their own lives, alleging that ChatGPT encouraged suicide and harmful delusions. — James Peckham, PC Magazine, 5 Oct. 2026 See All Example Sentences for harmful

Recent Examples of Synonyms for harmful

Adjective

That's on the heels of a 41-7 blowout at Northwestern that was ugly enough for Deion Sanders to dismiss a handful of players for conduct detrimental to the team days later.

— Amber Harding OutKick, FOXNews.com, 30 Sep. 2026
To that point, Carter wrote that if the NFL’s relationship with Fanatics were detrimental to the marketplace, there would be higher prices for consumers.

— Michael McCann, Sportico.com, 30 Sep. 2026

Definition of detrimental

Adjective

But for the most part, both are getting their points across, landing a few licks and, so far, avoiding the sort of major gaffe or damaging moment that could reshape the race.

— AJC.com, AJC.com, 7 Oct. 2026
The region stretching from North Dakota to Texas contains a large share of the country’s beef production, Hanson said, making prolonged drought there particularly damaging.

— Evan Moore, Charlotte Observer, 6 Oct. 2026

Definition of damaging

Adjective

Meanwhile, the financial clout of the industry has grown considerably, resulting in a new, more dangerous problem.

— Kent Sepkowitz, STAT, 5 Oct. 2026
Attempting to de-escalate the scare, Rospotrebnadzor declared the regional sanitary situation stable after secondary testing showed no traces of dangerous pathogens linked to Shipilova’s research.

— Mrigakshi Dixit, Interesting Engineering, 5 Oct. 2026

Definition of dangerous

Adjective

Retaliation is described as an adverse employment action connected to an activity protected by a law under its jurisdiction.

— William Jones, Sacbee.com, 2 Oct. 2026
Eating Sweetened Foods With Protein Eating protein alongside sugary snacks can help stabilize your blood sugar and minimize the spikes that lead to a host of adverse health effects.

— Kelly Burch, Verywell Health, 2 Oct. 2026

Definition of adverse

Adjective

Why is Indonesia experiencing its worst ever wildfire season?

— TheWeek, TheWeek, 2 Oct. 2026
Interior designers and professional organizers say most kitchens hide usable square footage in plain sight, trapped behind clutter, bad habits and bulky gear that could be stored smarter or edited out entirely.

— Lauren Jarvis-Gibson, Kansas City Star, 1 Oct. 2026

Definition of bad

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“Harmful.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/harmful. Accessed 8 Oct. 2026.

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Synonyms of harmful

adjective

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