The phrase "coming up to snuff" refers to achieving a high standard or meeting expectations. Antonyms for this phrase might include "falling short," "failing," or "underperforming." Other possible antonyms could include "inefficient," "ineffective," "inadequate," or "unacceptable." These words suggest a sense of disappointment or dissatisfaction with a person or situation that does not meet the desired level of quality. Alternatively, antonyms might highlight a lack of effort, motivation, or skill, such as "lazy," "unmotivated," or "incompetent." Ultimately, the antonyms for "coming up to snuff" emphasize a failure to achieve a particular standard, whether that be in terms of ability, performance, or attitude.