The word "haymaker" has two main meanings, and I’ll explain both of them.
Meaning: In boxing or fighting, a "haymaker" is a very strong punch that can knock someone down or make it hard for them to continue fighting.
Meaning: A "haymaker" can also refer to a machine used on farms that helps dry out hay faster and more evenly.
In boxing, a "haymaker" often implies not just any punch, but one that is delivered with the intention of ending the fight. In farming, the term may refer to specific types of machinery or techniques used to improve hay production.
There are no direct idioms or phrasal verbs that use "haymaker," but you might say "throw a punch" or "land a hit" when discussing boxing.
So, "haymaker" can refer to a powerful punch in a boxing match or a machine used on farms.