Antonyms are words that have the opposite meaning to another word. In the case of "coming up snuff," its antonyms could include "falling short," "failing," "deficient," or "inadequate." These words imply a lack of success or achievement, which is the opposite of "coming up snuff" - a phrase denoting success and meeting expectations. By using these antonyms, we can add depth and nuance to our writing, conveying a sense of disappointment or failure. Conversely, using the phrase "coming up snuff" can evoke feelings of achievement and success, making it a useful tool in writing that aims to inspire or motivate.