casus belli
Americannoun
plural
casus bellinoun
-
an event or act used to justify a war
-
the immediate cause of a quarrel
Etymology
Origin of casus belli
1840–50; < New Latin: literally, occurrence of war
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.
In his speech announcing the war, Mr. Trump explained the extensive casus belli to the American people.
From The Wall Street Journal • Mar. 2, 2026
Rather, this narrow goal may be intended to serve as an official casus belli, giving Russian diplomats something to cite, however implausible, particularly at the United Nations.
From New York Times • Feb. 24, 2022
He could well seize on some alleged affront in the negotiations themselves as a casus belli.
From Washington Post • Dec. 14, 2021
One of the few voices that challenged Polk’s casus belli was Abraham Lincoln, then serving in Congress.
From The New Yorker • May 13, 2019
The casus belli was usually the desire to avenge an insult or gain status, not the wish for conquest.
From "1491" by Charles C. Mann
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.
