adjective
Other Word Forms
Derived 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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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.
Africa has 10 teams in the tournament, and Senegal and Morocco stand out as the most dangerous of the group.
From Los Angeles Times • Jun. 7, 2026
The mere possibility makes betting against him dangerous.
From The Wall Street Journal • Jun. 7, 2026
They point to climate change, aging water infrastructure, and weak monitoring systems as factors that could allow dangerous amoebae to spread and become harder to control.
From Science Daily • Jun. 6, 2026
Heteropessimism exists alongside heterosexuality not because being straight is terrible or embarrassing or out of fashion, but because it is, first and foremost, an institution — one that in many places remains dangerous to spurn.
From Salon • Jun. 3, 2026
It’s an incredibly dangerous task, and Hans is soon captured.
From "At Last She Stood" by Erin Entrada Kelly
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.
