DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   smoothbore
       adj 1: of a firearm; not having rifling or internal spiral
              grooves inside the barrel [syn: unrifled, smoothbore]
              [ant: rifled]
       n 1: a firearm that has no rifling