I. ˈbəŋ noun
Etymology: Middle English, from Middle Dutch bonne, bonghe
Date: 15th century
1. : the stopper especially in the bunghole of a cask ; also : bunghole
2. : the cecum or anus especially of a slaughtered animal
II. transitive verb
Date: 1589
1. : to plug with or as if with a bung
2. British : throw , toss
bung a spanner into the works — P. G. Wodehouse