1. To rush, flow, or pour down (something). A great flood of water swept down the ravine. A frigid wind swept down from the summit, chilling us to our bones.

2. To clean or clear something by brushing its surface very lightly and quickly, as with a broom or brush. A noun or pronoun can be used between "sweep" and "down." Make sure you sweep the floor down before you begin mopping, or you'll just smear dirt around. She swept down the ancient tombstone so she could decipher the inscriptions.