However, depending on the desired meaning, you could consider these options:
To emphasize the source:
* Pre-monition: Indicates a forewarning, often seen as a feeling or intuition (already exists)
* Divine-monition: Highlights a warning from a divine source
* Prophetical-monition: Emphasizes a warning based on prophecy
To highlight the nature of the warning:
* Urgent-monition: Stresses the importance of immediate action
* Stern-monition: Indicates a strong and serious warning
* Solemn-monition: Emphasizes the gravity and seriousness of the warning
To emphasize the impact:
* Impactful-monition: Highlights the powerful influence of the warning
* Transformative-monition: Suggests the warning causes a change in behavior or thinking
Ultimately, the best prefix depends on the specific context and the desired nuance.