The antonyms for the phrase "previous practice" can include various terms depending upon the context in which it is being used. For instance, the antonym of "previous" can be "future" or "upcoming," indicating that there is no past history or practice. Similarly, the opposite of "practice" can be "novice," "beginner," or "inexperience," suggesting a lack of practice or expertise. Moreover, some other antonyms might include "deficiency," "negligence," or "omission," indicating a complete absence of any prior practice. Thus, depending on the context, various terms can act as antonyms for the phrase "previous practice.