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.
Researchers have long believed that amyloid buildup helps create the conditions in which harmful tau tangles develop.
From Science Daily ● Oct. 15, 2026
"The way we avoid grief can be really harmful to us," Dawson said.
From BBC ● Oct. 15, 2026
Aside from attempts to calm and entice locals, Amazon took a harder-line approach earlier this month, warning the public that the moratoriums could be harmful.
From The Wall Street Journal ● Oct. 15, 2026
Wells dismissed those fears on Thursday and said a previous clause in the draft legislation that would have granted ministerial powers to define harmful content had been removed.
From Barron's ● Oct. 15, 2026
Advocates of “co-sleeping,” meanwhile, warn that sleeping alone is harmful to a baby’s psyche and that he should be brought into the “family bed.”
From "Freakonomics: A Rogue Economist Explores the Hidden Side of Everything" by Steven D. Levitt
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Get a wordDefinitions 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.
