What is prefix for intelligent?

There isn't one single, universally accepted prefix for "intelligent". However, depending on the specific context, you could use:

* Intelli-: This is the most common and widely used prefix for "intelligent." Examples include "intelligentsia," "intelligibility," and "intellectual."

* Soph-: This prefix, meaning "wise," is also related to intelligence. Examples include "sophisticated" and "sophistry."

* Sag-: This prefix, meaning "wise," is less common but can be used in certain contexts. Examples include "sagacious" and "sage."

The best prefix to use will depend on the specific meaning you want to convey.