The word "slip-up" refers to a careless mistake or error. Some possible antonyms for "slip-up" include words such as accuracy, precision, correctness, attention to detail, and diligence. These opposite terms suggest that a person or process is focused on doing things correctly and avoiding mistakes. Rather than being careless or inattentive, someone who embodies these antonyms is deliberate, thorough, and conscientious. By striving for accuracy and avoiding slip-ups, individuals and organizations can achieve their goals and maintain a high level of quality in their work.