slapper

/ˈslæpər/
noun
  1. A person or thing that slaps, such as a hand or an object used to strike.
    • The toy was a plastic slapper that made a loud noise when you hit it against the table.
    • In the comedy show, the clown used a giant slapper to make funny sounds.
    • The old fishing net had a slapper attached to scare away birds.
Synonyms