[deyn-jer-uh s, deynj-ruh s]


full of danger or risk; causing danger; perilous; risky; hazardous; unsafe.
able or likely to cause physical injury: a dangerous criminal.

Origin of dangerous

1175–1225; Middle English da(u)ngerous domineering, fraught with danger < Old French dangereus threatening, difficult, equivalent to dangier (see danger) + -eus -ous
Related formsdan·ger·ous·ly, adverbdan·ger·ous·ness, nounnon·dan·ger·ous, adjectivenon·dan·ger·ous·ly, adverbnon·dan·ger·ous·ness, nounqua·si-dan·ger·ous, adjectivequa·si-dan·ger·ous·ly, adverbsem·i·dan·ger·ous, adjectivesem·i·dan·ger·ous·ly, adverbsem·i·dan·ger·ous·ness, nounun·dan·ger·ous, adjectiveun·dan·ger·ous·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for dangerous

Contemporary Examples of dangerous

Historical Examples of dangerous

  • What a dangerous character you'd be if you were sent to match silks!

    The Spenders

    Harry Leon Wilson

  • Philip was getting into a dangerous mood with his sentimentalism.


    Thomas Wentworth Higginson

  • My dear, I'm glad and thankful you've done with that dreadful, dangerous game.

  • He had got a dangerous game to play, and his plans were vague and shadowy.

    Life in London

    Edwin Hodder

  • Such conduct is as wicked and dangerous to the state as any that can be conceived.

British Dictionary definitions for dangerous



causing danger; perilous
Derived Formsdangerously, adverbdangerousness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for dangerous

early 13c., "difficult, arrogant, severe" (the opposite of affable), from Anglo-French dangerous, Old French dangeros (12c., Modern French dangereux), from danger (see danger).

In Chaucer, it means "hard to please, reluctant to give;" sense of "full of danger, risky" is from late 15c. Other words used in this sense included dangersome (1560s), dangerful (1540s). Related: Dangerously.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with dangerous


see little knowledge is a dangerous thing; live dangerously.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.