An act or event that provokes or is used to justify war.
A matter or occasion of war; an excuse or a reason for declaring war: as, the right of search claimed by Great Britain constituted a casus belli in 1812.
An act seen as justifying or causing a war.
(The American Heritage® Dictionary of the English Language, 5th Edition)
casus belli /kā″səs bĕl′ī, kä″səs bĕl′ē/
noun
An act or event that provokes or is used to justify war.
A matter or occasion of war; an excuse or a reason for declaring war: as, the right of search claimed by Great Britain constituted a casus belli in 1812.
An act seen as justifying or causing a war.
(The American Heritage® Dictionary of the English Language, 5th Edition)