prohibit

This term carries a strong sense of officialdom and authority. It is most frequently used in legal, regulatory, or institutional contexts to describe a formal ban. The tone is sterile and absolute, suggesting a rule that is codified rather than a mere suggestion or a personal preference.

In a non-legal sense, the word describes an insurmountable barrier or a practical impossibility. While "prevent" suggests stopping an action from occurring, "prohibit" emphasizes the restrictive force or the prohibitive cost that makes the action unfeasible.