A person who finds it difficult or takes a long time to learn something new. It's not that she's unintelligent, she is just a slow study when it comes to mathematics. Your son is a little bit of a slow study, but if he continues to practice and come to lessons, I have no doubt we can make a pianist of him yet.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
a person who is slow to learn things. (Compare this to a slow study.) Fred, who is a slow study, never caught on to the joke.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.