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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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.
On Sunday, the UAE said a drone strike had triggered a fire near its nuclear power station, calling the incident a "dangerous escalation".
From BBC • May 18, 2026
Experts say that losing muscle at such a rate can be especially dangerous for those over 50 or with osteoporosis or limited mobility as it could lead to an increased risk of injury.
From The Wall Street Journal • May 17, 2026
“Behavioral contagion” is why secondhand smoke is truly dangerous, as Frank points out.
From Slate • May 15, 2026
In my 30 years’ experience in markets—less discreetly focused on oil markets than some of the others here—that has been a dangerous tactic.
From Barron's • May 15, 2026
Spun with magic that Red insisted was dangerous.
From "Rump: The (Fairly) True Story of Rumpelstilskin" by Liesl Shurtliff
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.
