Source : WordNet®

knock down
     v 1: cause to come or go down; "The policeman downed the heavily
          armed suspect"; "The mugger knocked down the old lady
          after she refused to hand over her wallet" [syn: {down},
           {cut down}, {push down}, {pull down}]
     2: knock down with force; "He decked his opponent" [syn: {deck},
         {coldcock}, {dump}, {floor}]