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
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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.
“Losing them to invasive grassland means a more dangerous fire regime that threatens biodiversity, and the people and livelihoods that depend on Catalina Island.”
From Los Angeles Times ● Sep. 2, 2026
“That can be a dangerous combination,” he said.
From MarketWatch ● Sep. 2, 2026
On board, he said the sailors likely had to battle the uncertainty of how long their deployment was going to last, while also avoiding complacency and maintaining sharp focus in a dangerous environment.
From The Wall Street Journal ● Sep. 2, 2026
The Himalayan nation has limited resources to confront destruction on such a scale, and the disaster is stark warning of the dangerous fragility of its mountain environment in a rapidly heating world.
From Barron's ● Sep. 2, 2026
“Come, let’s get back before we are found. Humans can be just as dangerous, and I do not have an enchantment to make me invisible.”
From "The Way to Rio Luna" by Zoraida Cordova
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.
