whooper Syllabification: (whoop·er)Pronunciation: /ˈ(h)wo͞opər, ˈho͞opər/Definition of whooper noun (also whooper swan) 1a large migratory swan with a black and yellow bill and a loud trumpeting call, breeding in northern Eurasia and Greenland. Cygnus cygnus, family Anatidae 2short for whooping crane.whooper in other Oxford dictionaries Definition of whooper in the British & World English dictionary