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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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 The same poll found that 53% of adults now consider even moderate drinking harmful. — Ryan Brennan, Miami Herald, 11 Aug. 2026 The plaintiffs allege that addictive algorithms and a lack of guardrails around harmful online content have led to a rise in depression, anxiety, and body image issues. — Miranda Jeyaretnam, Time, 11 Aug. 2026 A broad spectrum sunscreen with an SPF of 30 or higher is your best defense against the sun's harmful rays. — Lauren Bostwick, CBS News, 11 Aug. 2026 Modern technology and techniques are capable of monitoring water quality, detecting harmful pathogens and eliminating them. — Joan Rose, The Conversation, 10 Aug. 2026 See All Example Sentences for harmful

Recent Examples of Synonyms for harmful

Adjective

The reduction in state investments and holding back promised funding to cover our faculty raises will have detrimental consequences to our institution, to us as students, and to the state’s future health care workforce.

— Opinion, Hartford Courant, 5 Aug. 2026
This development was approved after years of environmental studies and reviews by multiple state regulatory agencies and the Pittsburg City Council that concluded that there was no detrimental impact on the environment.

— CBS News, CBS News, 5 Aug. 2026

Definition of detrimental

Adjective

More damaging, employees gradually learn that raising concerns means navigating the leader's emotional reaction before addressing the actual issue.

— Rodger Dean Duncan, Forbes.com, 13 Aug. 2026
The main threats are expected to be damaging winds, hail and possible tornadoes.

— Michelle Simmons, ABC News, 12 Aug. 2026

Definition of damaging

Adjective

And the very review of the arch that identified its adverse effects is in the crosshairs of the administration.

— Edward Keegan, Chicago Tribune, 9 Aug. 2026
The Coastal Commission is widely expected to take any adverse ruling to court, potentially arguing that the federal government can’t deny a state its fundamental rights — in this case, a say over projects that affect its economy — over politics.

— Andre Mouchard, Oc Register, 9 Aug. 2026

Definition of adverse

Adjective

Sensing a disconnect or worse, a feeling of being forgotten, Campbell this summer invited some of the men who wrote those letters to campus.

— Dana O’Neil, CNN Money, 14 Aug. 2026
Dry weather periods are expected in Colorado, and wildfires tend to be worse during these times.

— Callie Zanandrie, CBS News, 14 Aug. 2026

Definition of bad

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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 15 Aug. 2026.

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Synonyms of harmful

adjective

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