haymaker

noun3

1. •
   A person or machine which harvests or prepares tall grass for use as animal fodder.

   • A long rank of haymakers—men and women—proceeded with their rakes, the white shirt-sleeves, straw bonnets, and ruddy faces, radiant in the bath of sunshine. — 1853
2. •
   (informal) A particularly powerful punch, especially one which knocks down an opponent, thrown like a scythe chop for cutting hay, as agricultural haymakers used to have strong arms.

   • The saga of Newt Gingrich's ethics suddenly resembles a brawl between blindfolded boxers who flail away so wildly that each lands a haymaker on his own jaw. — 1997
3. •
   (figurative) Any decisive blow, shock, or forceful action.