casus belli

noun
ca·​sus bel·​li | \ ˈkä-səs-ˈbe-ˌlē How to pronounce casus belli (audio) , ˈkā-səs-ˈbe-ˌlī How to pronounce casus belli (audio) \
plural casus belli

Definition of casus belli

: an event or action that justifies or allegedly justifies a war or conflict

Examples of casus belli in a Sentence

Recent Examples on the Web These days, a casus belli can be declared in broad daylight and in time for the evening news, complete with a live enemy caught red-handed trying to remove the evidence. Kevin Baker, Harper's magazine, "The Deep State of Dementia," 19 Aug. 2019 That Kaiser Wilhelm II could have possibly been the definitive casus belli of World War I ignores the depth of complexity and a geopolitical situation that cannot be compared with the modern Trump era. WSJ, "Comparison Unfair to Wilhelm II and Trump," 11 Nov. 2018 And that’s just in one Bush department, thus leaving out the false casus belli in Iraq or the yawning deficits or the financial collapse of 2008. T.a. Frank, The Hive, "A Note to Woke Washington: The Bush Administration Was So Much Worse," 4 May 2018 In the days following the session in Burbank, Sitrick worked with Shamrock executives on a letter of resignation from Roy to Eisner that not only would deny the chairman the pleasure of ousting Roy but would be a casus belli as well. Los Angeles Magazine, "Harvey Weinstein’s New Crisis PR Man Once Handled Rush Limbaugh, R. Kelly, and Accused Catholic Priests," 19 Dec. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'casus belli.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of casus belli

circa 1841, in the meaning defined above

History and Etymology for casus belli

New Latin, occasion of war

Keep scrolling for more

Learn More about casus belli

Statistics for casus belli

Time Traveler for casus belli

The first known use of casus belli was circa 1841

See more words from the same year

More from Merriam-Webster on casus belli

Rhyming Dictionary: Words that rhyme with casus belli

Comments on casus belli

What made you want to look up casus belli? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

to spread as a report or rumor

Get Word of the Day daily email!

Test Your Vocabulary

Confusing Words—A Quiz

  • alice with tweedle dee and tweedle dum
  • I invented a brand new toaster robot and ______ it "Sir Toasts-a-Lot."
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!