v.1. To trim back or cut down something that grows from the ground: Unfortunately, you didn't just cut the grass—you mowed down all the potato plants. We mowed the brush down with scythes.
2. To destroy or incapacitate someone or something as if by cutting or driving into the ground: The machine gunners mowed down hundreds of enemy troops within the first ten minutes of fighting. I tried to tackle the runner, but he just mowed me down. The gang drove by with machine guns and mowed the informant down in front of his house.
3. To overwhelm someone or something: The experienced debater mowed down the opposition with persuasive arguments.