What is the term for a person who studies but lacks knowledge?

There isn't a single perfect term for someone who studies but lacks knowledge. 

Here are a few options depending on the nuance you want to convey:

• Grind (informal): This describes someone who studies excessively, often memorizing facts but not necessarily understanding them deeply.
• Book smart: This refers to someone with knowledge gained solely from books and studying, lacking practical experience or real-world application.
• Dabbler: This describes someone who studies a subject superficially, without a deep understanding.

Other options depending on the specific situation:

• Novice: A beginner who is still learning the basics.
• Nescient (formal): This is a strong term that describes someone who is completely unaware or ignorant of a subject.