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.
Additional allegations included forced labor on fishing vessels and reliance on harmful pesticides and antibiotics.
From Los Angeles Times ● Oct. 9, 2026
Jennifer Taylor, National Union of Students Cymru president, said the comments were "dangerous" and "harmful"
From BBC ● Oct. 8, 2026
The lunar surface is exposed to intense temperature changes, harmful ionizing radiation, and frequent impacts from tiny space rocks.
From Science Daily ● Oct. 8, 2026
Jennifer Taylor, National Union of Students Cymru president, said the comments were "dangerous, harmful and are reinforcing a toxic culture on our campuses that must be tackled head on".
From BBC ● Oct. 8, 2026
Millions of gallons of water wasted, millions of lights burning, millions of pieces of litter, much of it harmful.
From "My Life with the Chimpanzees" by Jane Goodall
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.
