deleterious
Americanadjective
-
injurious to health.
deleterious gases.
-
harmful; injurious.
deleterious influences.
- Synonyms:
- noxious, destructive, hurtful, pernicious
- Antonyms:
- beneficial
adjective
Other Word Forms
Etymology
Origin of deleterious
1635–45; < Greek dēlētḗrios destructive, adj. derivative of dēlētḗr destroyer, equivalent to dēlē- variant stem of dēleîsthai to hurt, injure + -tēr agent suffix + -ios adj. suffix; see -ious
Explanation
If something is deleterious, it does harm or makes things worse. Smoking has obvious deleterious effects on your health, not to mention your social life. My parents were worried that their divorce would have a deleterious effect on us kids, but in the end it was less harmful than watching them fight all the time. For most plants, a lack of sunlight has very deleterious consequences, but there are some plants that actually do very well in the dark. It's a wonder, given how well-established the science is, that we continue to do things that are deleterious to the fragile ecosystem. We must be willing to live with the deleterious effects.
Vocabulary lists containing deleterious
100 Top "SAT" Words
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Grade 10, List 4
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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.
Demand destruction is among the many deleterious consequences of oil near $100 a barrel, said Pavel Molchanov, investment strategy analyst at Raymond James.
From MarketWatch • Apr. 14, 2026
When they met in Munich last month, California Gov. Gavin Newsom sought his views on curbing the addictive and deleterious effects of social media on children.
From The Wall Street Journal • Mar. 27, 2026
If one deteriorates, the other is almost certain to do so as well, with deleterious consequences.
From Barron's • Mar. 7, 2026
This duality of the natural and spiritual world is not wholly unique to radical Protestantism, but it has certainly showed up in a variety of deleterious ways.
From Salon • May 26, 2025
And weight carried around the middle is more deleterious than extra pounds in the butt.
From "Counting by 7s" by Holly Goldberg Sloan
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.
