adjective
Other Word Forms
- dangerously adverb
- dangerousness noun
- nondangerous adjective
- nondangerously adverb
- nondangerousness noun
- quasi-dangerous adjective
- quasi-dangerously adverb
- semidangerous adjective
- semidangerously adverb
- semidangerousness noun
- undangerous adjective
- undangerously adverb
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 ( 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.
“If anyone asks: What is the most dangerous thing that could happen to Iran and the region?” he said.
From The Wall Street Journal • Apr. 15, 2026
Experts are blaming the trend on a sharp increase in the noble false widow spider, which has been described as "the most dangerous spider breeding in Britain".
From BBC • Apr. 13, 2026
“But if the next step is a naval clash, attacks on Gulf energy infrastructure, or a widening of regional military operations, then the market will start to price a much more dangerous scenario,” she cautioned.
From Barron's • Apr. 13, 2026
Professor David Lalloo, from the Liverpool School of Tropical Medicine says the bites from false widow spiders "are not dangerous".
From BBC • Apr. 13, 2026
All the years of being told it was dangerous have left a mark and I’m shaking as I reach up to open the hatch.
From "Code Name Kingfisher" by Liz Kessler
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.
