Student, a mere youngster to be Italian (5)
I believe the answer is:
pupil
'student' is the definition.
(pupil can mean a student at a school)
'a mere youngster to be italian' is the wordplay.
I cannot really see how this works, but
'youngster' could be 'pup' (a pup is a young dog) and 'pup' is present in the answer.
'italian' could be 'i' (abbreviation for Italian) and 'i' is located in the answer.
A single letter 'l' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for pupil that I've seen before include "One under instruction" , "Learner at educational institution" , "Learner in the eye?" , "A student at school or eye part" , "Centre of iris, in the eye" .)