Possibly lets out to a pupil (5)
I believe the answer is:
tells
'possibly lets out to a pupil' is the definition.
I can't judge whether this definition defines the answer.
'possibly lets out to a pupil' is the wordplay.
'possibly' indicates an anagram.
'out' is an insertion indicator.
'to a pupil' becomes 'L' (as in L-plates for a learner driver).
'lets' anagrammed gives 'tels'.
'tels' enclosing 'l' is 'TELLS'.
Can you help me to learn more?
(Other definitions for tells that I've seen before include "Counts" , "Narrates" , "Informs, recounts" .)