From Longman Dictionary of Contemporary Englishknockout punch/blowknockout punch/blow informala) a hard hit that knocks someone down so that they cannot get up again b) an action or event that causes defeat or failure High interest rates have been a knockout blow to the business. → knockout
Examples from the Corpus
knockout punch/blow• But the new West Indies proved encouragingly resilient, repeatedly getting up off the canvas to deliver the final knockout punch.• Great passing; good running, but they lacked a knockout punch.• That seven eighty-one was like a knockout punch.• The business was reeling from what appeared to have been the knockout punch.• He may not have a knockout punch, but he does have good moves all the way to the bell.• It was a knockout punch of which Indurain, Hinault or Merckx would have been proud.• And then, as if to deliver the knockout blow to his scheme, the phone rang.• If people will use the vaccine available, it is possible to give paralytic polio a knockout blow within the next year. 