One whose pupils are not yet fully developed? (13)
I believe the answer is:
schoolteacher
'one' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for schoolteacher that I've seen before include "Educator" , "Instructor" , "tutor" , "Master, say" , "Chips perhaps" .)