The phrase "wipes slate clean" means to start fresh or to erase past mistakes. Antonyms for this phrase would indicate the opposite, such as clinging to old grudges or holding onto past mistakes. Words like "grudges," "animosity," "resentment," "rancor," or "vengeance" all convey negative and unforgiving feelings that do not allow a person to move on. Another antonym for "wipes slate clean" would be "dwelling," which means to focus on something negative or unproductive. To truly move forward and start anew, one must let go of past grievances and embrace forgiveness and understanding.