Definition of casus belli in English:
noun (plural same)
An act or situation provoking or justifying war.
- As the Romans liked a casus belli to justify their aggressive activities, it is not always possible to be certain about the real circumstances behind their intervention.
- France countered by getting Russia to propose a general congress, intended to isolate Austria and provoke a casus belli.
- The failure to disarm is probably a casus belli.