The phrase "clean up one's act" refers to the act of improving one's behavior, moral conduct or lifestyle. However, there are several antonyms for this phrase that connote the opposite meanings. Instead of cleaning up one's act, an individual could "mess up" their conduct, indicating a behavioral regression. Alternatively, one could choose to be "sloppy" in their ways or exhibit "lackadaisical" attitudes towards improving themselves. The person could further choose to be "negligent" or demonstrate "reckless" behavior, meaning a lack of concern or responsibility for their personal conduct. Overall, there is a broad scope of words that mean the opposite of "cleaning up one's act.
