adjective
Other Word Forms
Etymology
Origin of dangerous
First recorded in 1175–1225; Middle English da(u)ngerous “domineering, fraught with danger,” from Old French dangereus “threatening, difficult,” equivalent to dangier ( see danger) + -eus -ous
Explanation
Use the word dangerous to describe anything that can potentially cause serious harm, like a snarling pit bull or an icy, treacherous road. The earliest meaning of the word dangerous was "difficult or arrogant." When Geoffrey Chaucer wrote "The Canterbury Tales" in the 1300s, he used dangerous to mean "hard to please." Gradually the meaning changed, so that by the late fifteenth century, dangerous meant "liable to cause hurt" or "risky." Just as popular were two other danger-related words that we don't use anymore today: dangersome and dangerful, which at the time could be used interchangeably with dangerous.
Vocabulary lists containing dangerous
Words Every Pirate Should Know
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"Volcano!"
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"Brothers in Hope"
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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.
The line between giving just enough personal information for a better prompt, and dangerous oversharing, can be thin when you’re interacting with a chatbot.
From MarketWatch • Jul. 1, 2026
A prolonged and dangerous heatwave will intensify across a large swath of the US this week, bringing scorching daytime heat, high humidity and stifling overnight temperatures, forecasters predict.
From BBC • Jun. 30, 2026
“A market that might support that kind of activity, I think, is a dangerous market.”
From Slate • Jun. 30, 2026
Against Switzerland, its center back received a red card in the 80th minute for a dangerous tackle that denied a goal scoring opportunity.
From The Wall Street Journal • Jun. 30, 2026
It wasn’t until Buzz, Dan, and the boys heard the crew’s relief that they realized how dangerous the situation had been near the ground.
From "Mountain of Fire" by Rebecca E. F. Barone
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.
