General:
* Ignoramus: A person who is ignorant or uninformed.
* Dunce: A foolish or stupid person.
* Lout: A clumsy, insensitive person.
* Boor: A rude and insensitive person.
* Buffoon: A clownish or foolish person.
* Simpleton: A person lacking in intelligence.
* Charlatan: A person who pretends to have knowledge or skills they do not possess.
Focused on Learning:
* Dilettante: A person who dabbles in an art or subject without serious study.
* Amateur: A person who engages in an activity for pleasure rather than professionally.
* Beginner: A person who is just starting to learn something.
Focused on Academia:
* Drop-out: A person who leaves school or a course of study before completing it.
* Truant: A student who stays away from school without permission.
* Non-conformist: A person who does not follow accepted standards or practices.
The best antonym will depend on the specific meaning you want to convey.