1. an overwhelming or decisive victory, as by a political candidate who wins in all or almost all election districts.
2. the winning of all the prizes, rounds, contests, etc., in a competition or of all the games in a series.
3. a thorough or sweeping change, esp. one effected by the large-scale removal or elimination of unwanted persons or things: The new president made a clean sweep when he joined the company, replacing all the department heads.