harmful
Americanadjective
adjective
Other Word Forms
Etymology
Origin of harmful
First recorded before 1000; Middle English; Old English hearmful; see harm, -ful
Explanation
Things that are harmful hurt people, or are likely to hurt them. Listening to loud music through headphones can be harmful to your hearing. Harmful is an adjective that comes in handy when you're talking about things that cause injury to someone or damage something. Burning coal can be harmful to the environment, and eating too much candy can be harmful for your teeth. Harmful words can hurt someone's feelings and harmful actions might put them in danger. The Old English hearm, "hurt, evil, or grief," is at the root of harmful.
Vocabulary lists containing harmful
Earth Day
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Unfavorable
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Scientists have long thought that worker bees help shield queens from contamination by filtering harmful substances out of the food they provide.
From Science Daily ● Aug. 22, 2026
The UK probe will look into whether TikTok is doing enough under UK law to protect children from harmful content.
From Barron's ● Aug. 21, 2026
But business organisations from both sides of the border have urged for a deal to be reached, cautioning that additional tariffs between the two major trading partners would be harmful for both countries.
From BBC ● Aug. 19, 2026
The extension is welcome news for Canadian negotiators and for businesses on both sides of the border, who have warned that the new tariffs would be harmful to both countries.
From BBC ● Aug. 19, 2026
“It’s the loveliest gift. No one can say this one is harmful or foolish.”
From "Ella Enchanted" by Gail Carson Levine
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
