The phrase "priority directive" is commonly used to refer to an important mandate or instruction that requires immediate attention or action. However, there are several synonyms that can be used interchangeably with this phrase, such as "urgent order," "critical command," "essential mandate," "key instruction," "crucial directive," and "vital demand." Each of these alternative phrases conveys a similar sense of urgency and importance, and can be used in a wide range of contexts. By using these synonyms, writers can add variety and clarity to their language while still conveying the same essential message about the significance and immediacy of a particular directive or command.