2Also with capital initials. A nickname for the honourable discharge badge given to ex-service personnel during the Second World War (1939–45); the eagle depicted on such a badge.
Origin
1930s. From ruptured + duck.
Definition of ruptured duck in US English:
ruptured duck
nounˌrʌptʃəd ˈdʌk
US Military slang
1A damaged aircraft.
2Also with capital initials. A nickname for the honourable discharge badge given to ex-service personnel during the Second World War (1939–45); the eagle depicted on such a badge.