Student making a light admission? (5)

I believe the answer is:

pupil

I'm a little stuck... Click here to teach me more about this clue!

'student' is the definition.
(pupil can mean a student at a school)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for pupil that I've seen before include "One studying" , "one may see through!" , "One under instruction" , "Eye's centre" , "One being taught" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.