Moaning Min·nie, moaning Minnie /ˌməʊnɪŋ ˈmɪni/ noun 1. infml someone who is never satisfied and is always complaining
2 a) in World War II, the name of a German weapon that made a screaming noise when it was fired
b) in World War II, a name for the siren (=machine that makes a long, loud warning sound) that warned people that enemy planes were about to drop bombs