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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
"Volcano!"
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
"Brothers in Hope"
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
“There is a high risk for dangerous heat illness for anyone, especially for the very young, the very old, those without air conditioning, and those active outdoors,” the heat advisory said.
From Los Angeles Times ● Jul. 13, 2026
“This shows just how irrational investor expectations are becoming, and that sets a dangerous precedent,” Puckrin said, adding that SK Hynix is vulnerable given how heavily retail investors drive the South Korean stock market.
From MarketWatch ● Jul. 13, 2026
Officers arrested the lorry's 48-year-old driver, from Derbyshire, at the scene on suspicion of causing death by dangerous driving.
From BBC ● Jul. 12, 2026
Therapists warn that chatbot advice delivered without clinical context can be dangerous and delay vital treatment for eating disorders.
From The Wall Street Journal ● Jul. 11, 2026
It sounds dangerous and frightening, not beautiful like a tropical fish.
From "South of Somewhere" by Kalena Miller
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.
