'Popgun' definitions:

Definition of 'popgun'

(from WordNet)
noun
Plaything consisting of a toy gun that makes a popping sound

Definition of 'Popgun'

From: GCIDE
  • Popgun \Pop"gun`\, n. A child's gun; a tube and rammer for shooting pellets, with a popping noise, by compression of air. [1913 Webster]