whacker

/ˈwækər/
noun
  1. A person or thing that whacks or hits.
    • He's a big whacker when it comes to playing baseball.
    • She used a carpet whacker to beat the dust out of the rug.
    • The old whacker of a machine broke down again.
  2. Something unusually large or impressive of its kind.
    • He caught a whacker of a wave while surfing.
    • That fish was a real whacker—it weighed over 20 pounds.
    • She told a whacker of a story that no one believed.
Synonyms