Noun (usually military term): an officially recognized state of
hostility or war between two or more belligerents; often expressed as the phrase "in anger", now commonly used to describe any state of
conflict between
opposing parties.
As of the current date, the United States remains the only nation ever to have used
atomic weapons in anger, against the Japanese Empire in August
1945, in order to bring an end to Japanese resistance during
World War II.