The phrase "goofing up" means to make a mistake or mess up. There are several antonyms for this phrase, including succeeding, achieving, accomplishing, performing well, and excelling. These antonyms all imply a positive result or outcome, indicating that the opposite of goofing up is to do something well and effectively. Other antonyms for goofing up include being competent, proficient, capable, and skilled. These words all suggest that the person is knowledgeable or experienced in their task and can complete it without making errors or mistakes. Overall, the antonyms for goofing up emphasize the importance of competence, skill, and success in achieving one's goals.