sweep one off feet

sweep one off one's feet

 and knock one off one's feet 
1. Lit. to knock someone down. The wind swept me off my feet. Bill punched Bob playfully, and knocked him off his feet.
2. Fig. to overwhelm someone (figuratively). Mary is madly in love with Bill. He swept her off her feet. The news was so exciting that it knocked me off my feet.
See also: feet, off, one, sweep