When it comes to describing something that impresses or astonishes, "knocks dead" is a common phrase used to convey this feeling. However, there are plenty of synonyms to replace this phrase and add variety to your language. Some examples of synonyms for "knocks dead" could be "blows away," "wows," "amazes," "astounds," "stuns," "floors," "startles," and "surprises." Each of these words can add a new dimension and level of excitement to your writing or conversation. By incorporating more synonyms into your vocabulary, you can enhance the quality and richness of your language, and communicate more effectively with others.