Digressionary refers to something that is prone to digressions, or deviations from the main topic. Its antonyms, therefore, are words that describe something that is direct, focused, and to the point. These antonyms include terms such as concise, on-topic, relevant, straight, to-the-point, and concise. Another set of antonyms that could be used are words that refer to strict adherence to a plan. This would include terms like methodical, disciplined, systematic, structured, and organized. In a conversation or discussion, avoiding digressions and staying focused on the main topic is crucial for effective communication, engagement, and audience retention.