The antonyms for the phrase "doest well enough" can be various based on the context. However, some common antonyms for this phrase are "underperforming," "failing," "struggling," "inadequate," "insufficient" and "unsatisfactory." For instance, if a student's academic performance is not up to the mark, then we can say that he or she is not doing well enough. On the contrary, if someone is performing exceptionally well, then we can say that they are excelling in their field. Therefore, the antonyms of "doest well enough" are essential to understand the degree and level of performance of an individual or entity.