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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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.
Meanwhile, human babies have unusually large heads relative to body size, resulting in a difficult and sometimes dangerous birth process – often requiring outside assistance.
From Science Daily • Jul. 11, 2026
While chatbots are the new Dr. Google for a lot of people seeking medical advice, eating-disorder therapists say advice offered to their patients without the context of their diagnoses is downright dangerous.
From The Wall Street Journal • Jul. 11, 2026
Cycling’s premier event is dangerous, extreme, constant with the human dramas and twists.
From The Wall Street Journal • Jul. 10, 2026
The BBC has exclusively obtained the parole board's report about Scatchard's release, which said he was "frank" with them about the seriousness of his offences, and understood how dangerous he was.
From BBC • Jul. 10, 2026
It was a good idea—they were trying to keep people away from what could be a very dangerous situation.
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.
