There are several synonyms for the phrase "knocked down." One of these is "brought down," which implies that something or someone was forcibly taken from a higher position. Another synonym is "toppled over," which refers to something that falls from a standing position. A third option is "collapsed," which suggests a more sudden and dramatic fall, such as a building or structure coming apart. "Tumbled down" is another option, which brings to mind the image of something falling over and rolling down a hill. Finally, "knocked to the ground" is another similar phrase that implies the forceful removal of something from its original position.